Artemisia capillaris is a herbaceous aromatic and therapeutic plant. The genetic variability among individuals of Artemisia capillaris from state of Terengganu, Malaysia was examined by using the random amplified poly...Artemisia capillaris is a herbaceous aromatic and therapeutic plant. The genetic variability among individuals of Artemisia capillaris from state of Terengganu, Malaysia was examined by using the random amplified polymorphic DNA （RAPD） technique to assess the polymorphism at the species level, The samples from differences regional in Terengganu State. The genomic DNA was extracted from the samples leaves using Sarkosyl method. The results produced by the machine showed clear RAPD banding pattern. Fifty-seven oligonucleotide primers were screened and five primers were selected （OPA 04, OPA 09, OPA 16, OPA 17 and OPA 18） to amplify DNA from five samples of Artemisia capillaris from State of Terengganu, Malaysia. A total of 135 RAPD fragments （RAPDs） with all polymorphic fragments （100%） with size ranging from 250--3000 bp were scored from the population. Genetic distance for samples ranges from 0.0000 to 0.320000. For similarity index samples ranges from 0.0000 to 0.7547.展开更多
Laminaria and Saccharina have recently been recognized as two independent clades from the former genus Laminaria. Traditional morphological taxonomy is being challenged by molecular evidence from both nucleus and plas...Laminaria and Saccharina have recently been recognized as two independent clades from the former genus Laminaria. Traditional morphological taxonomy is being challenged by molecular evidence from both nucleus and plastid. Intensive work is in great demand from the perspective of genome colinearity. In this study, 118 sequence-tagged site(STS) markers were screened for phylogenetic analyses, 29 based on genome sequences, while 89 were based on expressed sequence tag(EST) sequences. EST-based STS marker development(29.37%) had an effi ciency twice as high as genome-sequence-based development(9.48%) as a result of high conservation of gene transcripts among the relative species. S. ochotensis, S. religiosa, S. japonica, and L. hyperborea showed great homogeneity in all 118 STS markers. Our result supports the view that the diversifi cation between the genera Saccharina and Laminaria was a more recent event and that Saccharina and Laminaria shared high phylogenetic affi nity. However, when it came to the single nucleotide polymorphism(SNP) level among the 41 SNPs, L. hyperborea owned 29 unique SNPs against 12 within the left three Saccharina species and 12 of the 13 indels were supposedly unique for L. hyperborea, indicated by its high variability. Originating from homologous ancestors, species between the recently diverged genera Laminaria and Saccharina may have taken in enough mutations at the SNP level only, in spite of different evolutionary strategies for better adaptation to the environment. Our study lays a solid foundation from a new perspective, although more accurate phylogenetic analysis is still needed to clarify the evolutionary traces between the genera Saccharina and Laminaria.展开更多
Symbiodinium sp. occurs in a symbiotic association with various marine invertebrates, including the seleractinian corals. Understanding the flexibility and specificity in coral-algal symbiosis can have important impli...Symbiodinium sp. occurs in a symbiotic association with various marine invertebrates, including the seleractinian corals. Understanding the flexibility and specificity in coral-algal symbiosis can have important implications for predicting the future of coral reefs in the era of global climate change. In the present study, we conducted Symbiodinium phylotype analysis, based on polymerase chain reaction and restriction fragment length polymorphism （PCR-RFLP）, in the scleractinian coral, Galaxeafascicularis, from a tropical fringing reef in Hainan Island, over a 1-yr period. Our results showed that Galaxea fascicularis could associate with Symbiodinium clade C and D either individually or simultaneously. However, during the sampling period, the Symbiodinium phylotype did not change significantly in the scleractinian coral Galaxeafascicularis, although the seawater temperature decreased sharply in the winter season. This study further suggests that the shift in Symbiodinium communities in response to seasonally fluctuating environments might not be a universal feature of coral-algal associations.展开更多
Littorina fabalis is an intertidal snail commonly living on the brown algae Fucus vesiculosus and showing frequent shell-color polymorphisms in the wild. The evolutionary mechanism underlying this polymorphism is curr...Littorina fabalis is an intertidal snail commonly living on the brown algae Fucus vesiculosus and showing frequent shell-color polymorphisms in the wild. The evolutionary mechanism underlying this polymorphism is currently unknown. Shell color variation was studied in mated and non-mated specimens of this species from different microareas in one locality from NW Spain, in order to estimate sexual selection and assortative mating that may （still） be operating in this population. The analyses across microareas allowed us to investigate frequency-dependent selection and assortative mating components, mechanisms that could maintain the polymorphism. The presence of shell scars caused by crab attacks, an environmental variable not related with sexual selection or assortative mating, was used as experimental control. This study provides new evidence of significant disas- sortative mating and some degree of sexual selection against some shell colors, supporting the results found 21 years ago in a similar study, i.e. in the same species and locality. The similarity of these estimates during the studied period suggests that this experimental approach is consistent and valid to be extended to other populations and organisms. In addition, sexual selection and assortative mating estimates did not change across microareas differing in shell color frequencies, suggesting than the polymor- phism can not be maintained by a frequency-dependent （sexual selection-based） mechanism. Our main hypothesis is that negative assortative mating could contribute to the maintenance of the polymorphism, perhaps by males showing distinct female color preferences when searching for mates [Current Zoology 58 （3）： 463-474, 2012].展开更多
Major histocompatibility complex （MHC） genes are critical members in both innate and adaptive immunity, and the association between their polymorphism and disease resistance has been reported in many teleosts. In th...Major histocompatibility complex （MHC） genes are critical members in both innate and adaptive immunity, and the association between their polymorphism and disease resistance has been reported in many teleosts. In the present study, we first investigated the genetic variation at the MHC II β gene in orange-spotted grouper （Epinephelus coioides） after a challenge with Singapore grouper iridovirus （SGIV）. The results reveal that a high polymorphism level of the MHC II β gene （H = 1.000; K = 20.206; π=0.081） and at least three loci exist in grouper. The rate of dN/dS in the peptide-binding region （PBR） and non-PBR were both 〉1, suggesting the loci were evolving under positive selection. A high ratio of heterozygous individuals （37.26 %） and high rate of dN/dS were discovered, suggesting that both heterozygote advantage and frequency-dependent selection might result in the high polymorphism levels in MHC II β genes in grouper. A total of 33 MHC II β alleles were identified from 40 high-susceptibility （HS） and 40 high-re- sistance group （HR） individuals, and 15 alleles were used in the association analysis. Three alleles, EPCO-DBB＊0302, EPCO-DBB＊0307, EPCO-DBB＊0603, and EPCO- DBB＊1001 were significantly associated with resistance ability to SG1V, and the EPCO-DBB＊0607 and EPCO-DBB＊1303 alleles were associated with susceptibility （P 〈 0.05）. To further confirm the association, another independent challenge experiment was performed. The result of association analysis in the verification test found that only EPCO-DBB＊1001 alleles were significantly asso- ciated with resistance to SGIV （P 〈 0.05）, while the other alleles showed no significance （P 〉 0.05） in the frequency distribution between HR and HS groups. Therefore, the EPCO-DBB＊ 1001 alleles could be used as a disease resis- tance-related MHC marker in the molecular marker-assisted selective breeding program of grouper.展开更多
文摘Artemisia capillaris is a herbaceous aromatic and therapeutic plant. The genetic variability among individuals of Artemisia capillaris from state of Terengganu, Malaysia was examined by using the random amplified polymorphic DNA （RAPD） technique to assess the polymorphism at the species level, The samples from differences regional in Terengganu State. The genomic DNA was extracted from the samples leaves using Sarkosyl method. The results produced by the machine showed clear RAPD banding pattern. Fifty-seven oligonucleotide primers were screened and five primers were selected （OPA 04, OPA 09, OPA 16, OPA 17 and OPA 18） to amplify DNA from five samples of Artemisia capillaris from State of Terengganu, Malaysia. A total of 135 RAPD fragments （RAPDs） with all polymorphic fragments （100%） with size ranging from 250--3000 bp were scored from the population. Genetic distance for samples ranges from 0.0000 to 0.320000. For similarity index samples ranges from 0.0000 to 0.7547.
基金Supported by the National High Technology Research and Development Program of China(863 Program)(No.2012AA10A406)the Science and Technology Development Project of Shandong Province,China(No.2006GG3205001)+2 种基金the National Basic Scientific Special Fund of the Ministry of Science and Technology,China(No.2007FY210500)the National Public Benefit Research Foundation of the State Bureau of Oceanography,China(No.200805075)the Research Fund for Basic Sciences of Higher Education by National Ministry of Finance and Education,China(No.201262003)
文摘Laminaria and Saccharina have recently been recognized as two independent clades from the former genus Laminaria. Traditional morphological taxonomy is being challenged by molecular evidence from both nucleus and plastid. Intensive work is in great demand from the perspective of genome colinearity. In this study, 118 sequence-tagged site(STS) markers were screened for phylogenetic analyses, 29 based on genome sequences, while 89 were based on expressed sequence tag(EST) sequences. EST-based STS marker development(29.37%) had an effi ciency twice as high as genome-sequence-based development(9.48%) as a result of high conservation of gene transcripts among the relative species. S. ochotensis, S. religiosa, S. japonica, and L. hyperborea showed great homogeneity in all 118 STS markers. Our result supports the view that the diversifi cation between the genera Saccharina and Laminaria was a more recent event and that Saccharina and Laminaria shared high phylogenetic affi nity. However, when it came to the single nucleotide polymorphism(SNP) level among the 41 SNPs, L. hyperborea owned 29 unique SNPs against 12 within the left three Saccharina species and 12 of the 13 indels were supposedly unique for L. hyperborea, indicated by its high variability. Originating from homologous ancestors, species between the recently diverged genera Laminaria and Saccharina may have taken in enough mutations at the SNP level only, in spite of different evolutionary strategies for better adaptation to the environment. Our study lays a solid foundation from a new perspective, although more accurate phylogenetic analysis is still needed to clarify the evolutionary traces between the genera Saccharina and Laminaria.
基金Supported by the National Natural Science Foundation of China(No.40830850)the Knowledge Innovation of Chinese Academy of Sciences(No.KZCX2-YW-227)
文摘Symbiodinium sp. occurs in a symbiotic association with various marine invertebrates, including the seleractinian corals. Understanding the flexibility and specificity in coral-algal symbiosis can have important implications for predicting the future of coral reefs in the era of global climate change. In the present study, we conducted Symbiodinium phylotype analysis, based on polymerase chain reaction and restriction fragment length polymorphism （PCR-RFLP）, in the scleractinian coral, Galaxeafascicularis, from a tropical fringing reef in Hainan Island, over a 1-yr period. Our results showed that Galaxea fascicularis could associate with Symbiodinium clade C and D either individually or simultaneously. However, during the sampling period, the Symbiodinium phylotype did not change significantly in the scleractinian coral Galaxeafascicularis, although the seawater temperature decreased sharply in the winter season. This study further suggests that the shift in Symbiodinium communities in response to seasonally fluctuating environments might not be a universal feature of coral-algal associations.
文摘Littorina fabalis is an intertidal snail commonly living on the brown algae Fucus vesiculosus and showing frequent shell-color polymorphisms in the wild. The evolutionary mechanism underlying this polymorphism is currently unknown. Shell color variation was studied in mated and non-mated specimens of this species from different microareas in one locality from NW Spain, in order to estimate sexual selection and assortative mating that may （still） be operating in this population. The analyses across microareas allowed us to investigate frequency-dependent selection and assortative mating components, mechanisms that could maintain the polymorphism. The presence of shell scars caused by crab attacks, an environmental variable not related with sexual selection or assortative mating, was used as experimental control. This study provides new evidence of significant disas- sortative mating and some degree of sexual selection against some shell colors, supporting the results found 21 years ago in a similar study, i.e. in the same species and locality. The similarity of these estimates during the studied period suggests that this experimental approach is consistent and valid to be extended to other populations and organisms. In addition, sexual selection and assortative mating estimates did not change across microareas differing in shell color frequencies, suggesting than the polymor- phism can not be maintained by a frequency-dependent （sexual selection-based） mechanism. Our main hypothesis is that negative assortative mating could contribute to the maintenance of the polymorphism, perhaps by males showing distinct female color preferences when searching for mates [Current Zoology 58 （3）： 463-474, 2012].
基金supported by China Postdoctoral Science Foundation Funded Project(2015M572380)National Basic Research Program of China(973)(2012CB114402)
文摘Major histocompatibility complex （MHC） genes are critical members in both innate and adaptive immunity, and the association between their polymorphism and disease resistance has been reported in many teleosts. In the present study, we first investigated the genetic variation at the MHC II β gene in orange-spotted grouper （Epinephelus coioides） after a challenge with Singapore grouper iridovirus （SGIV）. The results reveal that a high polymorphism level of the MHC II β gene （H = 1.000; K = 20.206; π=0.081） and at least three loci exist in grouper. The rate of dN/dS in the peptide-binding region （PBR） and non-PBR were both 〉1, suggesting the loci were evolving under positive selection. A high ratio of heterozygous individuals （37.26 %） and high rate of dN/dS were discovered, suggesting that both heterozygote advantage and frequency-dependent selection might result in the high polymorphism levels in MHC II β genes in grouper. A total of 33 MHC II β alleles were identified from 40 high-susceptibility （HS） and 40 high-re- sistance group （HR） individuals, and 15 alleles were used in the association analysis. Three alleles, EPCO-DBB＊0302, EPCO-DBB＊0307, EPCO-DBB＊0603, and EPCO- DBB＊1001 were significantly associated with resistance ability to SG1V, and the EPCO-DBB＊0607 and EPCO-DBB＊1303 alleles were associated with susceptibility （P 〈 0.05）. To further confirm the association, another independent challenge experiment was performed. The result of association analysis in the verification test found that only EPCO-DBB＊1001 alleles were significantly asso- ciated with resistance to SGIV （P 〈 0.05）, while the other alleles showed no significance （P 〉 0.05） in the frequency distribution between HR and HS groups. Therefore, the EPCO-DBB＊ 1001 alleles could be used as a disease resis- tance-related MHC marker in the molecular marker-assisted selective breeding program of grouper.
