Darwin’s theory of evolution believes that biological evolution is a process of natural selection. This theory has been supported by much evidence, but the internal biological mechanism is not clear. Here, I elaborat...Darwin’s theory of evolution believes that biological evolution is a process of natural selection. This theory has been supported by much evidence, but the internal biological mechanism is not clear. Here, I elaborate on the cycle of potassium resources on the earth and the biological utilization and efficiency, which may be the core mechanism of natural selection and affect the evolution of organisms and the development of human society.展开更多
In the field of anthropology, the uniparerttally inherited Y chromosome has long been used to trace the paternal lineage of the populations and to understand differences in migration and population genetics between ma...In the field of anthropology, the uniparerttally inherited Y chromosome has long been used to trace the paternal lineage of the populations and to understand differences in migration and population genetics between males and females, with additional advantages of small effective population size, suf- ficient markers, and population-specific haplotype distribution (Jobling and Tyler-Smith, 1995; Jin and Su, 2000; Underhill et al., 2000). Many such population studies have rested on the assumption that all the Y chromosome markers in the non- recombination regions are selectively neutral (Jobling and Tyler-Smith, 2003).展开更多
Cereal genes are classified into two distinct classes according to the guanine-cytosine (GC) content at the third codon sites (GC3). Natural selection and mutation bias have been proposed to affect the GC content....Cereal genes are classified into two distinct classes according to the guanine-cytosine (GC) content at the third codon sites (GC3). Natural selection and mutation bias have been proposed to affect the GC content. However, there has been controversy about the cause of GC variation. Here, we characterized the GC content of 1 092 paralogs and other single-copy genes in the duplicated chromosomal regions of the rice genome (ssp. indica) and classified the paralogs into GC3-rich and GC3-poor groups. By referring to out-group sequences from Arabidopsis and maize, we confirmed that the average synonymous substitution rate of the GC3-rich genes is significantly lower than that of the GC3-poor genes. Furthermore, we explored the other possible factors corresponding to the GC variation including the length of coding sequences, the number of exons in each gene, the number of genes in each family, the location of genes on chromosomes and the protein functions. Consequently, we propose that natural selection rather than mutation bias was the primary cause of the GC variation.展开更多
Aims Floral traits in animal-pollinated plants are proposed to be selected by the behavior of pollinators,which create differential fitness.However,fitness estimation is not trivial and there is no agreed or universal...Aims Floral traits in animal-pollinated plants are proposed to be selected by the behavior of pollinators,which create differential fitness.However,fitness estimation is not trivial and there is no agreed or universal measure of fitness.in plants,fitness can be measured in various ways,including the number of fruits or seeds,probability of survival,or growth rate.Methods Because each fitness measure can be associated with different pol-linator behavior,estimating pollinator-mediated selection on floral traits can differ among various fitness measures.We used the annual Mediterranean plant,Linum pubescens,as a model to assess the relative role of various fitness measures in estimating pollinator-mediated selection on floral traits.We compared four maternal fit-ness measures and estimated their relative advantage in assessing natural selection on floral traits of L.pubescens.To identify whether each trait is under pollinator-mediated selection,we used media-tional analysis.Important Findings We found that each floral trait was under natural selection assessed by a different fitness measure.The color combination of floral tube throat and stamen color was under selection when using seed mass as a fitness measure,and floral diameter was under positive direc-tional selection when the number of seeds or number of fruits was used as a fitness measure.Selection on floral color was not mediated by pollinators’visitation rates,while flower diameter showed par-tial pollinator-mediated selection.We conclude that using several fitness measures gives an insight into the mechanisms underlying phenotypic selection on a floral trait,and facilitates the understand-ing of pollinator-mediated selection.展开更多
Objective:To determine the genetic diversity of Plasmodium(P.)knowlesi isolates from Sabah,Malaysian Borneo and Peninsular Malaysia,targeting the S-type SSU rRNA gene and including aspects of natural selection and hap...Objective:To determine the genetic diversity of Plasmodium(P.)knowlesi isolates from Sabah,Malaysian Borneo and Peninsular Malaysia,targeting the S-type SSU rRNA gene and including aspects of natural selection and haplotype.Methods:Thirty-nine blood samples infected with P.knowlesi were collected in Sabah,Malaysian Borneo and Peninsular Malaysia.The S-type SSU rRNA gene was amplified using polymerase chain reaction,cloned into a vector,and sequenced.The natural selection and haplotype of the S-type SSU rRNA gene sequences were determined using DnaSP v6 and illustrated using NETWORK v10.This study's 39 S-type SSU rRNA sequences and eight sequences from the Genbank database were subjected to phylogenetic analysis using MEGA 11.Results:Overall,the phylogenetic analysis showed no evidence of a geographical cluster of P.knowlesi isolates from different areas in Malaysia based on the S-type SSU rRNA gene sequences.The S-type SSU rRNA gene sequences were relatively conserved and with a purifying effect.Haplotype sharing of the S-type SSU rRNA gene was observed between the P.knowlesi isolates in Sabah,Malaysian Borneo,but not between Sabah,Malaysian Borneo and Peninsular Malaysia.Conclusions:This study suggests that the S-type SSU rRNA gene of P.knowlesi isolates in Sabah,Malaysian Borneo,and Peninsular Malaysia has fewer polymorphic sites,representing the conservation of the gene.These features make the S-type SSU rRNA gene suitable for comparative studies,such as determining the evolutionary relationships and common ancestry among P.knowlesi species.展开更多
Jack London is one of the most outstanding naturalistic writers in America who composed many renowned full-length novels.Jack London’s short story,"To Build a Fire"is a good reflection of naturalistic tende...Jack London is one of the most outstanding naturalistic writers in America who composed many renowned full-length novels.Jack London’s short story,"To Build a Fire"is a good reflection of naturalistic tendencies.It chooses"To Build a Fire"so as to fully understand his perspective of naturalism.First,it provides a brief introduction to Jack London and this short story.Second,it specifically displays naturalism in this short story from four aspects.Among them,objective authenticity is the most distinctive feature in naturalistic elements.Meanwhile,his literature creation is also deeply influenced by Darwin’s theory of evolution.It aims to investigate gold seeker’s failure that reflects natural selection and theory of survival of the fittest.Finally,it concludes that only by respecting nature can human beings survive in natural selection.Through the analysis of gold seeker’s tragic fate,it warns that the readers should master wild survival skills and live in harmony with nature.展开更多
This paper presents the development process relating to the conceptual design of glass/renewable natural fibrereinforced polymer hybrid composite motorcycle side cover.Motorcycle side cover is a component frequently m...This paper presents the development process relating to the conceptual design of glass/renewable natural fibrereinforced polymer hybrid composite motorcycle side cover.Motorcycle side cover is a component frequently made from plastic or steel that functions on covering the motorcycle parts,components and systems such as frame,battery,electrical systems and mechanical systems.Function Analysis Systems Techniques(FAST)is used to identify the functions of motorcycle side cover.The right-side cover of motorcycle model SYM E-Bonus 110 has been physically studied to identify the competitive benchmarking criteria.The functions and competitive benchmarking criteria are then compiled and integrated with the environmental requirements to identify the Product Design Specifications(PDS).The coir fibre has been selected from six identified dominant renewable natural fibre used for automotive component through integration of Ranking Method and Quality Based Selection(QBS).Then the polypropylene matrix is selected after shortlisting the existing thermoplastic that is used with coir fibre and has high suitability for injection moulding manufacturing.The polypropylene matrix is then evaluated using Weighted Evaluation Matrix(WEM)by comparing to benchmark material which is Acrylonitrile Butadiene Styrene(ABS).After that,the conceptual design development of glass/renewable coir fibre-reinforced polypropylene motorcycle side cover is carried out using an integrated Theory of Inventive Problem Solving(TRIZ)and Morphological Chart,followed by final conceptual design selection using integration of Pugh Scoring Method and QBS.The conceptual design development intended on improving the biodegradability to reduce pollution to the environment.However,the usage of glass/coir fibre-reinforced polypropylene hybrid composite may increase the weight due to higher density.Four innovative design concepts have been developed and the selected final concept design has the most minimum number of ribs and minimum thickness with the same ratio of glass fibre and natural fibre composition.展开更多
1 Technology of natural materials Early man used conveniently shaped stones as tools. "Workshop" areas have been found with large numbers of stones, some showing signs of being worked. However, organic materials li...1 Technology of natural materials Early man used conveniently shaped stones as tools. "Workshop" areas have been found with large numbers of stones, some showing signs of being worked. However, organic materials like wood will decay under normal wet conditions in the presence of oxygen, so we won't find the same sort of evidence for wooden tools. It is safe to assume that early man used sticks as probes and clubs, and maybe even for making some sort of nestlike protection against the elements and predators, since we see chimpanzees and other animals doing this sort of thing. So wood, and ahnost certainly other plant materials such as fibrous leaves, and bone and other materials gleaned from dead animals, would be used from the earliest times. We need to know this in order to establish the idea that Man can be expected to have a long history of the use and manipulation of natural materials. This needs skills in choosing materials for certain uses on the basis of their mechanical properties, whether those properties are to do with the ease of shaping the material or the effectiveness of that material in use. Occasionally the material was chosen simply because it was readily available. If we find that a particular material was always used for a certain job, it's reasonable to deduce that Man was exerting materials selection criteria through experience.展开更多
Harsh environmental conditions often impose strong selection on the phenotype of natural populations through impacts on their fitness.For overwintering birds,winter is an important period for survival because the weat...Harsh environmental conditions often impose strong selection on the phenotype of natural populations through impacts on their fitness.For overwintering birds,winter is an important period for survival because the weather conditions in winter is usually severer than in other seasons and birds often suffer more thermoregulation costs while food is in short supply.Thus,the selective effect of weather conditions on phenotype in winter is expected to be strong.In this study,we examined the relationship of overwinter survival of Silver-throated Tits(Aegithalos glaucogularis)with their morphological traits under different levels of winter conditions(winters with and without snowstorms)to explore the differential selective effect of winter weather on their morphology.We found that regardless of whether the winter experienced a snowstorm,the female Silver-throated Tits with a smaller bill surface area or smaller bill depth and a smaller surface area:volume ratio were more likely to survive during the winter,which supported the hypothesis of selection for heat retention.Furthermore,the females with a smaller body length survived better than the larger females,indicating that the lesser food requirements for smaller body sizes may confer advantages during the winter when food availability was reduced.In addition,in agreement with the finding in many short-lived birds that survival rate increases with the increase of age,older(≥2-year-old)female Silver-throated Tits had higher overwinter survival than 1-year-old females.However,we did not find any correlation of morphological traits and age with survival in male Silver-throated Tits.These results illustrate differential selective effects of winter weather on female and male Silver-throated Tits and contribute to the knowledge of sex-specific selection on the phenotype of natural populations.展开更多
Evolution,adaptation and selection always exist in the evolutionary process of any species,which is the result of interrelation and interaction between living things and their environments,and the incarnation of natur...Evolution,adaptation and selection always exist in the evolutionary process of any species,which is the result of interrelation and interaction between living things and their environments,and the incarnation of natural laws in the evolutionary process of any species. Only if accurately understanding their connotation and interrelation among them,taking the evolution of living things as the line with centralizing the human sustainable development,dialectically unifying the active adaptation of the human being to their environments and oriented selection of nature and the society to species,we can acquire a better understanding of evolution of living things and a deeper understanding of the human sustainable development under biologically evolutionary background and uphold the true Darwinism,modern evolutionary point of view and the concept of current sustainable development in theory and in practice.展开更多
In the past decade there has been a profusion of studies highlighting covariation between individual differences in stress physiology and behavioural profiles, here called personalities. Such individual differences in...In the past decade there has been a profusion of studies highlighting covariation between individual differences in stress physiology and behavioural profiles, here called personalities. Such individual differences in ways of coping with stress are relevant both in biomedicine, since different personalities may experience a different stress and disease vulnerability, and in behavioural ecology, since their adaptive value and evolutionary maintenance are the subject of debate. However, the precise way in which individual stress differences and personalities are linked is unclear. Here we provide an updated overview of this covariation across different species and taxa, consider its functional significance and present working hypotheses for how behavioural and physiological responses to stress might be causally linked, affecting life-history traits such as dispersal and life-span [Current Zoology 56 (6): 728-740, 2010].展开更多
Synonymous codon usage pattern presumably reflects gene expression optimization as a result of molecular evolution. Though much attention has been paid to various model organisms ranging from prokaryotes to eukaryotes...Synonymous codon usage pattern presumably reflects gene expression optimization as a result of molecular evolution. Though much attention has been paid to various model organisms ranging from prokaryotes to eukaryotes, codon usage has yet been extensively investigated for model legume Medicago truncatula. In present study, 39 531 available coding sequences (CDSs) from M. truncatula were examined for codon usage bias (CUB). Based on analyses including neutrality plots, effective number of codons plots, and correlations between optimal codons frequency and codon adaptation index, we conclude that natural selection is a major driving force in M. truncatula CUB. We have identified 30 optimal codons encoding 18 amino acids based on relative synonymous codon usage. These optimal codons characteristically end with A or T, except for AGG and TTG encoding arginine and leucine respectively. Optimal codon usage is positively correlated with the GC content at three nucleotide positions of codons and the GC content of CDSs. The abundance of expressed sequence tag is a proxy for gene expression intensity in the legume, but has no relatedness with either CDS length or GC content. Collectively, we unravel the synonymous codon usage pattern in M. truncatula, which may serve as the valuable information on genetic engineering of the model legume and forage crop.展开更多
A proposition based on the fluctuation theorem in thermodynamics is formulated to quantitatively describe molecular evolution processes in biology. Although we cannot give full proof of its generality, we demonstrate ...A proposition based on the fluctuation theorem in thermodynamics is formulated to quantitatively describe molecular evolution processes in biology. Although we cannot give full proof of its generality, we demonstrate via computer simulation its applicability in an example of DNA in vitro evolution. According to this theorem, the evolution process is a series of exponentially rare fluctuations fixed by the force of natural selection展开更多
Endothelial PAS domain protein 1(EPAS1), also called hypoxia-inducible factor-2, is a key regulatory factor of hypoxic responses and plays an essential role in high-altitude adaptation in mammalian species. In this ...Endothelial PAS domain protein 1(EPAS1), also called hypoxia-inducible factor-2, is a key regulatory factor of hypoxic responses and plays an essential role in high-altitude adaptation in mammalian species. In this study, polymorphisms of EPAS1 were detected in 217 individuals from 2 Tibetan pig populations and 3 low-altitude pig breeds by DNA pooling, PCR-SSCP, PCR-RFLP and DNA sequencing methods. A total of 14 synonymous polymorphisms were identified in the coding region. The analysis suggested that SNP1(G963A), SNP7(C1632T), SNP10(G1929A) and SNP11(G1947A) showed potential association with high-altitude environment because of their particular variation patterns in Tibetan pigs. Linkage disequilibrium(LD) of these SNPs was analyzed. One common LD block including 5 SNPs clustering in exon 12 was identified in all studied pig populations. Haplotype H1(AGGTC) in LD block was dominant in Tibetan pigs(76.6 and 74.2% in Linzhi(LZ) and Chayu(CY) pigs, respectively) and segregated at higher frequency than that in low-altitude pig breeds(52.3, 58.7 and 56.2% in Wuzhishan(WZS), Min(M) and Laiwu(LW) pigs, respectively), indicating that H1 may relate to adaptation to high altitude in Tibetan pigs. These findings raise hope that EPAS1 gene can be a candidate gene that involved in adaptation of high altitude in Tibetan pigs.展开更多
Halogen chemistry constitutes an essential part in the industrial production of polymers and gains increasing attention as an attractive strategy to activate light alkanes that constitute natural gas. CeO2-based catal...Halogen chemistry constitutes an essential part in the industrial production of polymers and gains increasing attention as an attractive strategy to activate light alkanes that constitute natural gas. CeO2-based catalysts offer an exciting potential for advances in hydrogen halide recovery that enables a high efficiency of halogen-based processes for activation of small molecules. This review provides an overview of recently developed ceria-based catalysts in the context of polymer industry(polyvinyl chloride, polyurethanes, and polycarbonates) and activation of light hydrocarbons for natural gas upgrading. In addition, mechanistic insight and the challenges of ceria catalysts are provided, aiding the design of future catalytic materials and applications.展开更多
Tibeto-Burman(TB)people have endeavored to adapt to the hypoxic,cold,and high-UV high-altitude environments in the Tibetan Plateau and complex disease exposures in lowland rainforests since the late Paleolithic period...Tibeto-Burman(TB)people have endeavored to adapt to the hypoxic,cold,and high-UV high-altitude environments in the Tibetan Plateau and complex disease exposures in lowland rainforests since the late Paleolithic period.However,the full landscape of genetic history and biological adaptation of geographically diverse TB-speaking people,as well as their interaction mechanism,remain unknown.Here,we generate a whole-genome meta-database of 500 individuals from 39 TB-speaking populations and present a comprehensive landscape of genetic diversity,admixture history,and differentiated adaptative features of geographically different TB-speaking people.We identify genetic differentiation related to geography and language among TB-speaking people,consistent with their differentiated admixture process with incoming or indigenous ancestral source populations.A robust genetic connection between the Tibetan-Yi corridor and the ancient Yellow River people supports their Northern China origin hypothesis.We finally report substructure-related differentiated biological adaptative signatures between highland Tibetans and Loloish speakers.Adaptative signatures associated with the physical pigmentation(EDAR and SLC24A5)and metabolism(ALDH9A1)are identified in Loloish people,which differed from the high-altitude adaptative genetic architecture in Tibetan.TB-related genomic resources provide new insights into the genetic basis of biological adaptation and better reference for the anthropologically informed sampling design in biomedical and genomic cohort research.展开更多
Invasive alien species are primary drivers of biodiversity loss and species extinction.Smooth cordgrass(Spartina alterniflora)is one of the most aggressive invasive plants in coastal ecosystems around the world.Howeve...Invasive alien species are primary drivers of biodiversity loss and species extinction.Smooth cordgrass(Spartina alterniflora)is one of the most aggressive invasive plants in coastal ecosystems around the world.However,the genomic bases and evolutionary mechanisms underlying its invasion success have remained largely unknown.Here,we assembled a chromosome-level reference genome and performed phenotypic and population genomic analyses between native US and introduced Chinese populations.Our phenotypic comparisons showed that introduced Chinese populations have evolved competitive traits,such as earlyflowering time and greater plant biomass,during secondary introductions along China’s coast.Population genomic and transcriptomic inferences revealed distinct evolutionary trajectories of low-and high-latitude Chinese populations.In particular,genetic mixture among different source populations,together with in-dependent natural selection acting on distinct target genes,may have resulted in high genome dynamics of the introduced Chinese populations.Our study provides novel phenotypic and genomic evidence showing how smooth cordgrass rapidly adapts to variable environmental conditions in its introduced ranges.Moreover,candidate genes related toflowering time,fast growth,and stress tolerance(i.e.,salinity and submergence)provide valuable genetic resources for future improvement of cereal crops.展开更多
The evolution of light-skin pigmentation among Eurasians is considered as an adaptation to the high-latitude environments.East Asians are ideal populations for studying skin color evolution because of the complex envi...The evolution of light-skin pigmentation among Eurasians is considered as an adaptation to the high-latitude environments.East Asians are ideal populations for studying skin color evolution because of the complex environment of East Asia.Here,we report a strong selection signal for the pigmentation gene phenylalanine hydroxylase(PAH)in light-skinned Han Chinese individuals.The intron mutation rs10778203 in PAH is enriched in East Asians and is significantly associated with skin color of the back of the hand in Han Chinese males(P<0.05).In vitro luciferase and transcription factor binding assays show that the ancestral allele of rs10778203 could bind to SMAD2 and has a significant enhancer activity for PAH.However,the derived T allele(the major allele in East Asians)of rs10778203 decreases the binding activity of transcription factors and enhancer activity.Meanwhile,the derived T allele of rs10778203 shows a weaker ultraviolet radiation response in A375 cells and zebrafish embryos.Furthermore,rs10778203 decreases melanin production in transgenic zebrafish embryos after ultraviolet B(UVB)treatment.Collectively,PAH is a potential pigmentation gene that regulates skin tanning ability.Natural selection has enriched the adaptive allele,resulting in weakened tanning ability in East Asians,suggesting a unique genetic mechanism for evolutionary skin lightening in East Asians.展开更多
The evolution and maintenance of color clines is a classic topic of research in evolutionary ecology.However,studies analyzing the temporal dynamics of such clines are much less frequent,due to the difficulty of obtai...The evolution and maintenance of color clines is a classic topic of research in evolutionary ecology.However,studies analyzing the temporal dynamics of such clines are much less frequent,due to the difficulty of obtaining reliable data about past color distributions along environmen-tal gradients.In this article,we describe a case of decades-long temporal stability and directional change in a color cline of the marine snail Littorina saxatilis along the coastal inlet of the Ria de Vigo(NW Spain).L.saxatilis from this area shows a clear color cline with 3 distinct areas from the innermost to the more wave-exposed localities of the Ria:the inner,protected localities show an abundance of fawn-like individuals;the intermediate localities show a high diversity of colors;and the outer,wave-exposed localities show populations with a high frequency of a black and lineated morph.We compare data from the 1970s and 2022 in the same localities,showing that the cline has kept relatively stable for at least over half a century,except for some directional change and local variability in the frequency of certain morphs.Multiple regression analyses and biodiversity measures are presented to provide clues into the selective pressures that might be involved in the maintenance of this color cline.Future research avenues to properly test the explanatory power of these selective agents as well as the possible origins of the cline are discussed.展开更多
文摘Darwin’s theory of evolution believes that biological evolution is a process of natural selection. This theory has been supported by much evidence, but the internal biological mechanism is not clear. Here, I elaborate on the cycle of potassium resources on the earth and the biological utilization and efficiency, which may be the core mechanism of natural selection and affect the evolution of organisms and the development of human society.
基金supported by the National Excellent Youth Science Foundation of China (No. 31222030)the National Natural Science Foundation of China (Nos. 31071098 and 91131002)+2 种基金the Shanghai Rising-Star Program (No. 12QA1400300)the Shanghai Commission of Education Research Innovation Key Project (No. 11zz04)the Shanghai Professional Development Funding (No. 2010001)
文摘In the field of anthropology, the uniparerttally inherited Y chromosome has long been used to trace the paternal lineage of the populations and to understand differences in migration and population genetics between males and females, with additional advantages of small effective population size, suf- ficient markers, and population-specific haplotype distribution (Jobling and Tyler-Smith, 1995; Jin and Su, 2000; Underhill et al., 2000). Many such population studies have rested on the assumption that all the Y chromosome markers in the non- recombination regions are selectively neutral (Jobling and Tyler-Smith, 2003).
基金the State Key Basic Research and Development Plan of China(2003CB715900)the National Natural Science Foundation of China(90408015,30121003 and 30430030).
文摘Cereal genes are classified into two distinct classes according to the guanine-cytosine (GC) content at the third codon sites (GC3). Natural selection and mutation bias have been proposed to affect the GC content. However, there has been controversy about the cause of GC variation. Here, we characterized the GC content of 1 092 paralogs and other single-copy genes in the duplicated chromosomal regions of the rice genome (ssp. indica) and classified the paralogs into GC3-rich and GC3-poor groups. By referring to out-group sequences from Arabidopsis and maize, we confirmed that the average synonymous substitution rate of the GC3-rich genes is significantly lower than that of the GC3-poor genes. Furthermore, we explored the other possible factors corresponding to the GC variation including the length of coding sequences, the number of exons in each gene, the number of genes in each family, the location of genes on chromosomes and the protein functions. Consequently, we propose that natural selection rather than mutation bias was the primary cause of the GC variation.
文摘Aims Floral traits in animal-pollinated plants are proposed to be selected by the behavior of pollinators,which create differential fitness.However,fitness estimation is not trivial and there is no agreed or universal measure of fitness.in plants,fitness can be measured in various ways,including the number of fruits or seeds,probability of survival,or growth rate.Methods Because each fitness measure can be associated with different pol-linator behavior,estimating pollinator-mediated selection on floral traits can differ among various fitness measures.We used the annual Mediterranean plant,Linum pubescens,as a model to assess the relative role of various fitness measures in estimating pollinator-mediated selection on floral traits.We compared four maternal fit-ness measures and estimated their relative advantage in assessing natural selection on floral traits of L.pubescens.To identify whether each trait is under pollinator-mediated selection,we used media-tional analysis.Important Findings We found that each floral trait was under natural selection assessed by a different fitness measure.The color combination of floral tube throat and stamen color was under selection when using seed mass as a fitness measure,and floral diameter was under positive direc-tional selection when the number of seeds or number of fruits was used as a fitness measure.Selection on floral color was not mediated by pollinators’visitation rates,while flower diameter showed par-tial pollinator-mediated selection.We conclude that using several fitness measures gives an insight into the mechanisms underlying phenotypic selection on a floral trait,and facilitates the understand-ing of pollinator-mediated selection.
基金This study was supported by the Ministry of Higher Education,Malaysia(FRGS0322-SG-1/2013)Universiti Malaysia Sabah(GUG0521-2/2020).
文摘Objective:To determine the genetic diversity of Plasmodium(P.)knowlesi isolates from Sabah,Malaysian Borneo and Peninsular Malaysia,targeting the S-type SSU rRNA gene and including aspects of natural selection and haplotype.Methods:Thirty-nine blood samples infected with P.knowlesi were collected in Sabah,Malaysian Borneo and Peninsular Malaysia.The S-type SSU rRNA gene was amplified using polymerase chain reaction,cloned into a vector,and sequenced.The natural selection and haplotype of the S-type SSU rRNA gene sequences were determined using DnaSP v6 and illustrated using NETWORK v10.This study's 39 S-type SSU rRNA sequences and eight sequences from the Genbank database were subjected to phylogenetic analysis using MEGA 11.Results:Overall,the phylogenetic analysis showed no evidence of a geographical cluster of P.knowlesi isolates from different areas in Malaysia based on the S-type SSU rRNA gene sequences.The S-type SSU rRNA gene sequences were relatively conserved and with a purifying effect.Haplotype sharing of the S-type SSU rRNA gene was observed between the P.knowlesi isolates in Sabah,Malaysian Borneo,but not between Sabah,Malaysian Borneo and Peninsular Malaysia.Conclusions:This study suggests that the S-type SSU rRNA gene of P.knowlesi isolates in Sabah,Malaysian Borneo,and Peninsular Malaysia has fewer polymorphic sites,representing the conservation of the gene.These features make the S-type SSU rRNA gene suitable for comparative studies,such as determining the evolutionary relationships and common ancestry among P.knowlesi species.
文摘Jack London is one of the most outstanding naturalistic writers in America who composed many renowned full-length novels.Jack London’s short story,"To Build a Fire"is a good reflection of naturalistic tendencies.It chooses"To Build a Fire"so as to fully understand his perspective of naturalism.First,it provides a brief introduction to Jack London and this short story.Second,it specifically displays naturalism in this short story from four aspects.Among them,objective authenticity is the most distinctive feature in naturalistic elements.Meanwhile,his literature creation is also deeply influenced by Darwin’s theory of evolution.It aims to investigate gold seeker’s failure that reflects natural selection and theory of survival of the fittest.Finally,it concludes that only by respecting nature can human beings survive in natural selection.Through the analysis of gold seeker’s tragic fate,it warns that the readers should master wild survival skills and live in harmony with nature.
文摘This paper presents the development process relating to the conceptual design of glass/renewable natural fibrereinforced polymer hybrid composite motorcycle side cover.Motorcycle side cover is a component frequently made from plastic or steel that functions on covering the motorcycle parts,components and systems such as frame,battery,electrical systems and mechanical systems.Function Analysis Systems Techniques(FAST)is used to identify the functions of motorcycle side cover.The right-side cover of motorcycle model SYM E-Bonus 110 has been physically studied to identify the competitive benchmarking criteria.The functions and competitive benchmarking criteria are then compiled and integrated with the environmental requirements to identify the Product Design Specifications(PDS).The coir fibre has been selected from six identified dominant renewable natural fibre used for automotive component through integration of Ranking Method and Quality Based Selection(QBS).Then the polypropylene matrix is selected after shortlisting the existing thermoplastic that is used with coir fibre and has high suitability for injection moulding manufacturing.The polypropylene matrix is then evaluated using Weighted Evaluation Matrix(WEM)by comparing to benchmark material which is Acrylonitrile Butadiene Styrene(ABS).After that,the conceptual design development of glass/renewable coir fibre-reinforced polypropylene motorcycle side cover is carried out using an integrated Theory of Inventive Problem Solving(TRIZ)and Morphological Chart,followed by final conceptual design selection using integration of Pugh Scoring Method and QBS.The conceptual design development intended on improving the biodegradability to reduce pollution to the environment.However,the usage of glass/coir fibre-reinforced polypropylene hybrid composite may increase the weight due to higher density.Four innovative design concepts have been developed and the selected final concept design has the most minimum number of ribs and minimum thickness with the same ratio of glass fibre and natural fibre composition.
文摘1 Technology of natural materials Early man used conveniently shaped stones as tools. "Workshop" areas have been found with large numbers of stones, some showing signs of being worked. However, organic materials like wood will decay under normal wet conditions in the presence of oxygen, so we won't find the same sort of evidence for wooden tools. It is safe to assume that early man used sticks as probes and clubs, and maybe even for making some sort of nestlike protection against the elements and predators, since we see chimpanzees and other animals doing this sort of thing. So wood, and ahnost certainly other plant materials such as fibrous leaves, and bone and other materials gleaned from dead animals, would be used from the earliest times. We need to know this in order to establish the idea that Man can be expected to have a long history of the use and manipulation of natural materials. This needs skills in choosing materials for certain uses on the basis of their mechanical properties, whether those properties are to do with the ease of shaping the material or the effectiveness of that material in use. Occasionally the material was chosen simply because it was readily available. If we find that a particular material was always used for a certain job, it's reasonable to deduce that Man was exerting materials selection criteria through experience.
基金supported by the National Natural Science Foundation of China(31970421,31472011,31101644)。
文摘Harsh environmental conditions often impose strong selection on the phenotype of natural populations through impacts on their fitness.For overwintering birds,winter is an important period for survival because the weather conditions in winter is usually severer than in other seasons and birds often suffer more thermoregulation costs while food is in short supply.Thus,the selective effect of weather conditions on phenotype in winter is expected to be strong.In this study,we examined the relationship of overwinter survival of Silver-throated Tits(Aegithalos glaucogularis)with their morphological traits under different levels of winter conditions(winters with and without snowstorms)to explore the differential selective effect of winter weather on their morphology.We found that regardless of whether the winter experienced a snowstorm,the female Silver-throated Tits with a smaller bill surface area or smaller bill depth and a smaller surface area:volume ratio were more likely to survive during the winter,which supported the hypothesis of selection for heat retention.Furthermore,the females with a smaller body length survived better than the larger females,indicating that the lesser food requirements for smaller body sizes may confer advantages during the winter when food availability was reduced.In addition,in agreement with the finding in many short-lived birds that survival rate increases with the increase of age,older(≥2-year-old)female Silver-throated Tits had higher overwinter survival than 1-year-old females.However,we did not find any correlation of morphological traits and age with survival in male Silver-throated Tits.These results illustrate differential selective effects of winter weather on female and male Silver-throated Tits and contribute to the knowledge of sex-specific selection on the phenotype of natural populations.
基金Supported by Science Foundation of Chuxiong Normal University(06YJRC19)Key Subject Construction of Chuxiong Normal University (05YJJSXK03 )National Natural Science Foundation of China (30760040)~~
文摘Evolution,adaptation and selection always exist in the evolutionary process of any species,which is the result of interrelation and interaction between living things and their environments,and the incarnation of natural laws in the evolutionary process of any species. Only if accurately understanding their connotation and interrelation among them,taking the evolution of living things as the line with centralizing the human sustainable development,dialectically unifying the active adaptation of the human being to their environments and oriented selection of nature and the society to species,we can acquire a better understanding of evolution of living things and a deeper understanding of the human sustainable development under biologically evolutionary background and uphold the true Darwinism,modern evolutionary point of view and the concept of current sustainable development in theory and in practice.
文摘In the past decade there has been a profusion of studies highlighting covariation between individual differences in stress physiology and behavioural profiles, here called personalities. Such individual differences in ways of coping with stress are relevant both in biomedicine, since different personalities may experience a different stress and disease vulnerability, and in behavioural ecology, since their adaptive value and evolutionary maintenance are the subject of debate. However, the precise way in which individual stress differences and personalities are linked is unclear. Here we provide an updated overview of this covariation across different species and taxa, consider its functional significance and present working hypotheses for how behavioural and physiological responses to stress might be causally linked, affecting life-history traits such as dispersal and life-span [Current Zoology 56 (6): 728-740, 2010].
基金supported by the National Basic Research Program of China (2014CB138702)the National Natural Science Foundation of China (31502001)
文摘Synonymous codon usage pattern presumably reflects gene expression optimization as a result of molecular evolution. Though much attention has been paid to various model organisms ranging from prokaryotes to eukaryotes, codon usage has yet been extensively investigated for model legume Medicago truncatula. In present study, 39 531 available coding sequences (CDSs) from M. truncatula were examined for codon usage bias (CUB). Based on analyses including neutrality plots, effective number of codons plots, and correlations between optimal codons frequency and codon adaptation index, we conclude that natural selection is a major driving force in M. truncatula CUB. We have identified 30 optimal codons encoding 18 amino acids based on relative synonymous codon usage. These optimal codons characteristically end with A or T, except for AGG and TTG encoding arginine and leucine respectively. Optimal codon usage is positively correlated with the GC content at three nucleotide positions of codons and the GC content of CDSs. The abundance of expressed sequence tag is a proxy for gene expression intensity in the legume, but has no relatedness with either CDS length or GC content. Collectively, we unravel the synonymous codon usage pattern in M. truncatula, which may serve as the valuable information on genetic engineering of the model legume and forage crop.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10721403)the National Basic Research Program of China (Grant No. 2007CB814802)the Jun-Zheng Foundation at Peking University
文摘A proposition based on the fluctuation theorem in thermodynamics is formulated to quantitatively describe molecular evolution processes in biology. Although we cannot give full proof of its generality, we demonstrate via computer simulation its applicability in an example of DNA in vitro evolution. According to this theorem, the evolution process is a series of exponentially rare fluctuations fixed by the force of natural selection
基金supported by the National Natural Science Foundation of China(31272403)the Determination of Molecular Characterization for Genetically Modified Organism,China(2013ZX08012-002)the Livestock and Poultry Sharing Platform in China(2013)
文摘Endothelial PAS domain protein 1(EPAS1), also called hypoxia-inducible factor-2, is a key regulatory factor of hypoxic responses and plays an essential role in high-altitude adaptation in mammalian species. In this study, polymorphisms of EPAS1 were detected in 217 individuals from 2 Tibetan pig populations and 3 low-altitude pig breeds by DNA pooling, PCR-SSCP, PCR-RFLP and DNA sequencing methods. A total of 14 synonymous polymorphisms were identified in the coding region. The analysis suggested that SNP1(G963A), SNP7(C1632T), SNP10(G1929A) and SNP11(G1947A) showed potential association with high-altitude environment because of their particular variation patterns in Tibetan pigs. Linkage disequilibrium(LD) of these SNPs was analyzed. One common LD block including 5 SNPs clustering in exon 12 was identified in all studied pig populations. Haplotype H1(AGGTC) in LD block was dominant in Tibetan pigs(76.6 and 74.2% in Linzhi(LZ) and Chayu(CY) pigs, respectively) and segregated at higher frequency than that in low-altitude pig breeds(52.3, 58.7 and 56.2% in Wuzhishan(WZS), Min(M) and Laiwu(LW) pigs, respectively), indicating that H1 may relate to adaptation to high altitude in Tibetan pigs. These findings raise hope that EPAS1 gene can be a candidate gene that involved in adaptation of high altitude in Tibetan pigs.
文摘Halogen chemistry constitutes an essential part in the industrial production of polymers and gains increasing attention as an attractive strategy to activate light alkanes that constitute natural gas. CeO2-based catalysts offer an exciting potential for advances in hydrogen halide recovery that enables a high efficiency of halogen-based processes for activation of small molecules. This review provides an overview of recently developed ceria-based catalysts in the context of polymer industry(polyvinyl chloride, polyurethanes, and polycarbonates) and activation of light hydrocarbons for natural gas upgrading. In addition, mechanistic insight and the challenges of ceria catalysts are provided, aiding the design of future catalytic materials and applications.
基金the National Natural Science Foundation of China(82202078)the Center for Archaeological Science of Sichuan University(23SASA01).
文摘Tibeto-Burman(TB)people have endeavored to adapt to the hypoxic,cold,and high-UV high-altitude environments in the Tibetan Plateau and complex disease exposures in lowland rainforests since the late Paleolithic period.However,the full landscape of genetic history and biological adaptation of geographically diverse TB-speaking people,as well as their interaction mechanism,remain unknown.Here,we generate a whole-genome meta-database of 500 individuals from 39 TB-speaking populations and present a comprehensive landscape of genetic diversity,admixture history,and differentiated adaptative features of geographically different TB-speaking people.We identify genetic differentiation related to geography and language among TB-speaking people,consistent with their differentiated admixture process with incoming or indigenous ancestral source populations.A robust genetic connection between the Tibetan-Yi corridor and the ancient Yellow River people supports their Northern China origin hypothesis.We finally report substructure-related differentiated biological adaptative signatures between highland Tibetans and Loloish speakers.Adaptative signatures associated with the physical pigmentation(EDAR and SLC24A5)and metabolism(ALDH9A1)are identified in Loloish people,which differed from the high-altitude adaptative genetic architecture in Tibetan.TB-related genomic resources provide new insights into the genetic basis of biological adaptation and better reference for the anthropologically informed sampling design in biomedical and genomic cohort research.
基金supported by the National Key Research and Development Program of China (2022YFC2601100 to B.L.)the Natural Science Foundation of China (32030067 to J.-H.W.,31970235 to L.-F.L.,32171661 to R.-T.J.,and 31961133028 to B.L.).
文摘Invasive alien species are primary drivers of biodiversity loss and species extinction.Smooth cordgrass(Spartina alterniflora)is one of the most aggressive invasive plants in coastal ecosystems around the world.However,the genomic bases and evolutionary mechanisms underlying its invasion success have remained largely unknown.Here,we assembled a chromosome-level reference genome and performed phenotypic and population genomic analyses between native US and introduced Chinese populations.Our phenotypic comparisons showed that introduced Chinese populations have evolved competitive traits,such as earlyflowering time and greater plant biomass,during secondary introductions along China’s coast.Population genomic and transcriptomic inferences revealed distinct evolutionary trajectories of low-and high-latitude Chinese populations.In particular,genetic mixture among different source populations,together with in-dependent natural selection acting on distinct target genes,may have resulted in high genome dynamics of the introduced Chinese populations.Our study provides novel phenotypic and genomic evidence showing how smooth cordgrass rapidly adapts to variable environmental conditions in its introduced ranges.Moreover,candidate genes related toflowering time,fast growth,and stress tolerance(i.e.,salinity and submergence)provide valuable genetic resources for future improvement of cereal crops.
基金supported by the National Natural Science Foundation of China(32070579 and 32370664 to Z.Y.,31871449 and 32170813 to J.C.)the Natural Science Foundation of Henan(222300420067 to Z.Y.)+3 种基金State Key Laboratory of Genetic Resources and Evolution Grant(GREKF20-13 to Z.Y)Innovation and Entrepreneurship Training Program(2022cxcy568,2022cxcy717 and 2023cxcy475 to Z.Y.)the 1.3·5 project for disciplines of excellence of West China Hospital,Sichuan University(ZYGD23026 and 2024HXFH035)Science and Technologyy Department of Sichuan province(2024NSFSC0651).
文摘The evolution of light-skin pigmentation among Eurasians is considered as an adaptation to the high-latitude environments.East Asians are ideal populations for studying skin color evolution because of the complex environment of East Asia.Here,we report a strong selection signal for the pigmentation gene phenylalanine hydroxylase(PAH)in light-skinned Han Chinese individuals.The intron mutation rs10778203 in PAH is enriched in East Asians and is significantly associated with skin color of the back of the hand in Han Chinese males(P<0.05).In vitro luciferase and transcription factor binding assays show that the ancestral allele of rs10778203 could bind to SMAD2 and has a significant enhancer activity for PAH.However,the derived T allele(the major allele in East Asians)of rs10778203 decreases the binding activity of transcription factors and enhancer activity.Meanwhile,the derived T allele of rs10778203 shows a weaker ultraviolet radiation response in A375 cells and zebrafish embryos.Furthermore,rs10778203 decreases melanin production in transgenic zebrafish embryos after ultraviolet B(UVB)treatment.Collectively,PAH is a potential pigmentation gene that regulates skin tanning ability.Natural selection has enriched the adaptive allele,resulting in weakened tanning ability in East Asians,suggesting a unique genetic mechanism for evolutionary skin lightening in East Asians.
基金support from the Ministerio de Ciencia e Innovacion(PID2021-124930NB-I00)Xunta de Galicia(GRC,ED431C 2020-05)+2 种基金Centro singular de Investigacion de Galicia accreditation 2019-2022,and the European Union(European Regional Development Fund-ERDF)Juan Galindo was funded by a JIN project(Jovenes Investigadores,Ministerio de Ciencia,Innovacion y Universidades,RTI2018-101274-J-100)Juan Gefaell was funded by a Xunta de Galicia Predoctoral Research Contract(ED481A-2021/274).
文摘The evolution and maintenance of color clines is a classic topic of research in evolutionary ecology.However,studies analyzing the temporal dynamics of such clines are much less frequent,due to the difficulty of obtaining reliable data about past color distributions along environmen-tal gradients.In this article,we describe a case of decades-long temporal stability and directional change in a color cline of the marine snail Littorina saxatilis along the coastal inlet of the Ria de Vigo(NW Spain).L.saxatilis from this area shows a clear color cline with 3 distinct areas from the innermost to the more wave-exposed localities of the Ria:the inner,protected localities show an abundance of fawn-like individuals;the intermediate localities show a high diversity of colors;and the outer,wave-exposed localities show populations with a high frequency of a black and lineated morph.We compare data from the 1970s and 2022 in the same localities,showing that the cline has kept relatively stable for at least over half a century,except for some directional change and local variability in the frequency of certain morphs.Multiple regression analyses and biodiversity measures are presented to provide clues into the selective pressures that might be involved in the maintenance of this color cline.Future research avenues to properly test the explanatory power of these selective agents as well as the possible origins of the cline are discussed.