Basal physiological parameters in domesticated tree shrews (Tupaia belangeri chinensis)

Establishing non-human primate models of human diseases is an efficient way to narrow the large gap between basic studies and translational medicine. Multifold advantages such as simplicity of breeding, low cost of feeding and facility of operating make the tree shrew an ideal non-human primate model proxy. Additional features like vulnerability to stress and spontaneous diabetic characteristics also indicate that the tree shrew could be a potential new animal model of human diseases. However, basal physiological indexes of tree shrew, especially those related to human disease, have not been systematically reported. Accordingly, we established important basal physiological indexes of domesticated tree shrews including several factors: (1) body weight, (2) core body temperature and rhythm, (3) diet metabolism, (4) locomotor rhythm, (5) electroencephalogram, (6) glycometabolism and (7) serum and urinary hormone level and urinary cortisol rhythm. We compared the physiological parameters of domesticated tree shrew with that of rats and macaques. Results showed that (a) the core body temperature of the tree shrew was 39.59±0.05 °C, which was higher than that of rats and macaques; (b) Compared with wild tree shrews, with two activity peaks, domesticated tree shrews had only one activity peak from 17:30 to 19:30; (c) Compared with rats, tree shrews had poor carbohydrate metabolism ability; and (d) Urinary cortisol rhythm indicated there were two peaks at 8:00 and 17:00 in domesticated tree shrews, which matched activity peaks in wild tree shrews. These results provided basal physiological indexes for domesticated tree shrews and laid an important foundation for diabetes and stress-related disease models established on tree shrews.

Microsatellite analysis of variation among wild, domesticated, and genetically improved populations of blunt snout bream （Megalobrama amblycephala）

In the present study, the genetic diversity of one selected strain （Pujiang No. 1）, two domesticated populations （GA and HX） and four wild populations （LZ, YN, SS and JL） of blunt snout bream （Megalobrama amblycephala） was analyzed using 17 microsatellite markers. The results showed that an average of 4.88-7.65 number of alleles （A）; an average of 3.20-5.33 effective alleles （Ne）; average observed beterozygosity （Ho） of 0.6985-0.9044; average expected beterozygosity （He） of 0.6501--0.7805; and the average polymorphism information content （PIC） at 0.5706-0.7226. Pairwise FST value between populations ranged from 0.0307-0.1451, and Nei＇s standard genetic distance between populations was 0.0938-0.4524. The expected heterozygosities in the domesticated populations （GA and HX） were significantly lower than those found in three wild populations （LZ, SS and JL）, but no difference was detected when compared with the wild YN population. Likewise, no difference was found between the four wild populations or two domesticated populations. The expected heterozygosity in Pujiang No. 1 was higher than the two domesticated populations and lower than the four wild populations. Regarding pairwise Fsr value between populations, permutation test P-values were significant between the GA, HX and PJ populations, but not between the four wild populations. These results showed that the expected beterozygosity in the selected strain of blunt snout bream, after seven generations of selective breeding, was lower than that of wild populations, but this strain retains higher levels of genetic diversity than domesticated populations. The genetic differences and differentiation amongst wild populations, domesticated populations and the genetically improved strain of blunt snout bream will provide important conservation criteria and guide the utilization of germplasm resources.

Basal physiological parameters in domesticated tree shrews(Tupaia belangeri chinensis)

Establishing non-human primate models of human diseases is an efficient way to narrow the large gap between basic studies and translational medicine.Multifold advantages such as simplicity of breeding,low cost of feeding and facility of operating make the tree shrew an ideal non-human primate model proxy.Additional features like vulnerability to stress and spontaneous diabetic characteristics also indicate that the tree shrew could be a potential new animal model of human diseases.However,basal physiological indexes of tree shrew,especially those related to human disease,have not been systematically reported.Accordingly,we established important basal physiological indexes of domesticated tree shrews including several factors:(1)body weight,(2)core body temperature and rhythm,(3)diet metabolism,(4)locomotor rhythm,(5)electroencephalogram,(6)glycometabolism and(7)serum and urinary hormone level and urinary cortisol rhythm.We compared the physiological parameters of domesticated tree shrew with that of rats and macaques.Results showed that(a)the core body temperature of the tree shrew was 39.59±0.05°C,which was higher than that of rats and macaques;(b)Compared with wild tree shrews,with two activity peaks,domesticated tree shrews had only one activity peak from 17:30 to 19:30;(c)Compared with rats,tree shrews had poor carbohydrate metabolism ability;and(d)Urinary cortisol rhythm indicated there were two peaks at 8:00 and 17:00 in domesticated tree shrews,which matched activity peaks in wild tree shrews.These results provided basal physiological indexes for domesticated tree shrews and laid an important foundation for diabetes and stress-related disease models established on tree shrews.

A New Detecting Method for the Sequence Difference of CHD1 Gene on Sex Chromosomes Z and W in Domesticated Ducks of China

A new method for detecting the sequence differences of duck Chromo-helicase-DNA-Binding 1 （ CHD1 ） genes on sex chromosomes Z and W was established by amplifying DNA fragment length poly morphism, which aimed to solve some technical problems, such as the sex identification with nondamage, the misclassifc rate of artificial sex identification during embryonic period, and the injury caused by anal reversal identification method during neonatal period. The im- proved sex identification method was developed by DNA amplified fragment length polymorphism by using CHD1 gene sequence in bird. The sex identification PCR primers YPF/YPR were used, and the PCR product was cloned, sequenced and blasted; and the effectiveness and accuracy of this method were verified through liv- ing examples. 2% agarose gel electrophoresis was used to distinguish 495 bp CHD1-Z and 351 bp CHD1-W obtained by primer YPF/YPR. The female （ZW） dis- played two visible bands; while male （ZZ） had only one single band. It was proved that this method for detecting the sequence differences of duck CHD1 gene was visual and reliable, and the molecular marker provided was effective and precise in the sex molecular biological identification of domesticated duck in China.

Determination of Polyphenols Content in Carob Pulp from Wild and Domesticated Moroccan Trees

Carob (Ceratonia siliqua L.) fruit pulp from 12 wild and 8 domesticated trees from 15 Moroccan localities were investigated for their polyphenols contents: total polyphenols content (53.22 - 118.04 mg and 57.46 - 183.31 mg), total flavonoids (1.41 - 4.83 mg and 1.62 - 7.46 mg) and condensed tannins (1.47 - 7.36 mg and 1.85 - 6.66 mg) in one carob fresh pulp for wild and domesticated trees, respectively. Fruit pulp from trees in the same region shows variable contents in polyphenols, flavonoids and condensed tannins.

Potential dual expansion of domesticated donkeys revealed by worldwide analysis on mitochondrial sequences

Molecular studies on donkey mitochondrial sequences have clearly defined two distinct maternal lineages involved in domestication.However,domestication histories of these two lineages remain enigmatic.We therefore compared several population characteristics between these two lineages based on global sampling,which included 171 sequences obtained in this study(including Middle Asian,East Asian,and African samples)plus 536 published sequences(including European,Asian,and African samples).The two lineages were clearly separated from each other based on whole mitochondrial genomes and partial non-coding displacement loop(D-loop)sequences,respectively.The Clade I lineage experienced an increase in population size more than 8000 years ago and shows a complex haplotype network.In contrast,the population size of the Clade II lineage has remained relatively constant,with a simpler haplotype network.Although the distribution of the two lineages was almost equal across the Eurasian mainland,they still presented discernible but complex geographic bias in most parts of Africa,which are known as their domestication sites.Donkeys from sub-Saharan Africa tended to descend from the Clade I lineage,whereas the Clade II lineage was dominant along the East and North coasts of Africa.Furthermore,the migration routes inferred from diversity decay suggested different expansion across China between the two lineages.Altogether,these differences indicated non-simultaneous domestication of the two lineages,which was possibly influenced by the response of pastoralists to the desertification of the Sahara and by the social expansion and trade of ancient humans in Northeast Africa,respectively.

Genetic structure,gene flow pattern,and association analysis of superior germplasm resources in domesticated upland cotton(Gossypium hirsutum L.)

Gene flow patterns and the genetic structure of domesticated crops like cotton are not well understood.Furthermore,marker-assisted breeding of cotton has lagged far behind that of other major crops because the loci associated with cotton traits such as fiber yield and quality have scarcely been identified.In this study,we used 19 microsatellites to first determine the population genetic structure and patterns of gene flow of superior germplasm resources in upland cotton.We then used association analysis to identify which markers were associated with 15 agronomic traits(including ten yield and five fiber quality traits).The results showed that the upland cotton accessions have low levels of genetic diversity(polymorphism information content=0.427),although extensive gene flow occurred among different ecological and geographic regions.Bayesian clustering analysis indicated that the cotton resources used in this study did not belong to obvious geographic populations,which may be the consequence of a single source of domestication followed by frequent genetic introgression mediated by human transference.A total of 82 maker-trait associations were examined in association analysis and the related ratios for phenotypic variations ranged from 3.04% to 47.14%.Interestingly,nine SSR markers were detected in more than one environmental condition.In addition,14 SSR markers were co-associated with two or more different traits.It was noteworthy that NAU4860 and NAU5077 markers detected at least in two environments were simultaneously associated with three fiber quality traits(uniformity index,specific breaking strength and micronaire value).In conclusion,these findings provide new insights into the population structure and genetic exchange pattern of cultivated cotton accessions.The quantitative trait loci of domesticated cotton identified will also be very useful for improvement of yield and fiber quality of cotton in molecular breeding programs.

Shifts in Circulating Concentrations of Glucose in Domesticated Mammals: Is There a Consistent Adaptation to Domestication?

There have been marked changes in amylase gene number during human evolution resulting in shifts in carbohydrate metabolism. This has been related to utilization of starch. Similarly, there are changes in enzymes related to carbohydrate metabolism in dogs. Again, this has been linked to improving starch utilization following domestication. It was questioned as circulating concentrations of glucose is a good indicator of putative differences in carbohydrate metabolism across domesticated animals. Domesticated bovids had lower (p < 0.001) circulating concentrations of glucose than wild species in their respective subfamilies. Circulating concentrations of glucose were consistently lower (p < 0.001) in domesticated animals compared to either closely related wild species or the mean for wild species in their subfamilies (or families where there is insufficient data available). It is suggested that shift to lower circulating concentrations of glucose in domesticated animals is related to greater starch intake following domestication in a manner akin to the shifts in carbohydrate metabolism and amylase gene number in human evolution.

Microbiological Assessment and Shelf-Life Determination of Wheat Muffins Enriched with Domesticated African Emperor Moth (Gonimbrasia zambesina Walker) Caterpillar Flour

African emperor moth (Gonimbrasia zambesina) caterpillars are considered healthy food as they are rich in protein and unsaturated fats. In Kenya, G. zambesina caterpillars are predominantly found along the coastal region, where they emerge in during the short and the long rains. The caterpillars forage in the wild on mango (Mangifera indica) leaves and Euclea natalensis (Ericales: Ebenaceae) leaves. The caterpillars are consumed whole or may be transformed into fine flour. The caterpillars’ flour can be utilized in the bakery industry for the enrichment of bakery products since wheat (the major component of bakery products) is low in protein. However, consumers are concerned about the microbiological quality of bakery products enriched with insect flour. There are also concerns about the effect of these insects’ flour on the shelf life of bakery products since they have unsaturated fats. Therefore, this study evaluated the microbial quality and shelf life of wheat muffins enriched with G. zambesina caterpillar flour at 0%, 5%, 10%, 15%, and 20%. For all the samples analyzed, total viable count (TVC) was <30 cfu/g, total coliform count (TCC) was Salmonella spp, and Staphylococcus aureus were not detected. The colonies for yeast and moulds were <30 cfu/g throughout the evaluation time of 21 days. The PVs of wheat muffins increased with an increase in the substitution level. The PVs of enriched wheat muffins increased with an increase in storage time and temperature. The shelf-life of the wheat muffins decreased with an increase in the substitution level of wheat flour with G. zambesina caterpillar flour. The predicted shelf life of 0%, 5%, 10%, 15%, and 20% wheat muffins was 120.0 days, 111.0 days, 103.0 days, 102.0 days and 90.0 days, respectively. Therefore, wheat muffins enriched with G. zambesina caterpillar flour have good microbiological quality and shelf life.

Influences of Different Habitats on Asexual Propagation of Wild Gastrodia elata f. glauca being Domesticated in Ganzi

[Objective] The influences of different habitats on asexual propagation of wild Geg(abbreviation for Gastrodia elata Bl. f. glauca S. Chow) being domesticated in Ganzi prefecture was studied. [Method] The research trial was carried out in the following three kinds of habitats at the same time: the plastic greenhouses, the birch forest of shady slope and the shrubbery of sunny slope, and the results were analyzed with group data average hypothesis test method. [Result] The overall tuber(the juvenile tuber, the immature tuber and the mature tuber) yield and the mature tuber yield were both very significantly higher in the plastic greenhouses than in the other two types of habitats, and respectively reached 9.52 and 6.70 kg/m2; the mature tuber drying rate was dramatically or very dramatically lower in the plastic greenhouses than in the other two types of habitats, and was 23.84%; the stabilities of the overall tuber yield, the mature tuber yield and the drying rate were all reduced in the order of greenhouses, birch forest and shrubbery; and the dry mature tuber yield of the plastic greenhouses was the highest in the three kinds of habitats, and was 1.60 kg/m2. [Conclusion] A good habitat had to be created or chosen in the domesticating cultivation of the wild Geg in Ganzi prefecture. The preferred choice was the plastic greenhouse, the alternative one was the deciduous broadleaved forest of shady slope. The imitating wild planting of the wild Geg should be done in the warm moist deciduous broad-leaved forest of shady slope.

Imprinting at the KBTBD6 locus involves species-specific m ternal methylation and monoallelic expression in livestock animals

Background The primary differentially methylated regions(DMRs) which are maternally hypermethylated serve as imprinting control regions(ICRs) that drive monoallelic gene expression, and these ICRs have been investigated due to their implications in mammalian development. Although a subset of genes has been identified as imprinted, in-depth comparative approach needs to be developed for identification of species-specific imprinted genes. Here, we examined DNA methylation status and allelic expression at the KBTBD6 locus across species and tissues and explored potential mechanisms of imprinting.Results Using whole-genome bisulfite sequencing and RNA-sequencing on parthenogenetic and normal porcine embryos, we identified a maternally hypermethylated DMR between the embryos at the KBTBD6 promoter Cp G island and paternal monoallelic expression of KBTBD6. Also, in analyzed domesticated mammals but not in humans, non-human primates and mice, the KBTBD6 promoter Cp G islands were methylated in oocytes and/or allelically methyl-ated in tissues, and monoallelic KBTBD6 expression was observed, indicating livestock-specific imprinting. Further analysis revealed that these Cp G islands were embedded within transcripts in porcine and bovine oocytes which coexisted with an active transcription mark and DNA methylation, implying the presence of transcription-dependent imprinting.Conclusions In this study, our comparative approach revealed an imprinted expression of the KBTBD6 gene in domesticated mammals, but not in humans, non-human primates, and mice which implicates species-specific evolution of genomic imprinting.

Efficiency and effectiveness of systems for the treatment of domestic wastewater based on subsurface flow constructed wetlands in Jarabacoa, Dominican Republic

Constructed wetlands(CwW)are well known nature-based systems for water treatment.This study evaluated the efficiency and effectiveness of seven domestic wastewater treatment systems based on horizontal flow CWs in Jarabacoa,the Dominican Republic.The results showed that the CWs were efficient in reducing the degree of contamination of wastewater to levels below the Dominican wastewater discharge standards for parameters such as the 5-day biochemical oxygen demand(BOD5)and chemical oxygen demand,but not for the removal of phosphorus and fecal coliforms.In addition,a horizontal flow subsurface wetland in the peri-urban area El Dorado was evaluated in terms of the performance of wastewater treatment in tropical climatic conditions.The concentrations of heavy metals,such as zinc,copper,chromium,and iron,were found to decrease in the effluent of the wetland,and the concentrations for nickel and manganese tended to increase.The levels of heavy metals in the effluent were lower than the limit values of the Dominican wastewater discharge standards.The construction cost of these facilities was around 200 USD per population equivalent,similar to the cost in other countries in the same region.This study suggested some solutions to the improved performance of CWs:selection of a microbial flora that guarantees the reduction of nitrates and nitrites to molecular nitrogen,use of endemic plants that bioaccumulate heavy metals,combination of constructed wetlands with filtration on activated carbon,and inclusion of water purification processes that allow to evaluate the reuse of treated water.

Preliminary attempt to distinguish the domesticated pigs from wild boars by the methods of carbon and nitrogen stable isotope analysis

Despite great achievements in the origins of domestic pigs made by the methods of zooarchaeology and molecular biology,how to scientifically distinguish the domesticated pigs from wild boars during the early stage of pig domestication is still poorly understood.Compared to wild boar's diets which come from the natural environment,the diets of domestic pigs are more easily influenced by human feeding activities.Therefore,in principle,exploration of the dietary differences among pigs and understanding the impact on pig diets fed by humans can have great potential to differentiate between wild boars and domesticated pigs.To reveal dietary differences among pigs and distinguish the domesticated pigs from wild boars based on comparison with the diets of humans and other animals,we analyzed the carbon and nitrogen stable isotopes of human bones from Xiaojingshan Site and animal bones from Yuezhuang Site,both of which belong to Houli Culture in Shandong Province and date to about 8500―7500 years ago.The mean δ 13C value((-17.8 ± 0.3)‰) and δ 15N value((9.0±0.6)‰) in human collagen indicate that although millet agriculture began it was not the main subsistence strategy as millets are typical of C4 plants and that humans made a living mainly by gathering,hunting or raising some domesticated animals.The δ 13C value(-16.1‰) and δ 15N value(6.9‰) in the bovine suggest that C3 plants were dominant in its diet with some C4 plants complemented.The fish has lower δ 13C value(-24.9‰) and higher δ 15N value(8.8‰) than the bovine,which is the characteristic of the isotopic values from Eurasian freshwater fish.Based on the differences in carbon and nitrogen isotope values,the pigs can be divided into three groups.A group,composed of two pigs,has low δ 13C values(-18.1‰,-20.0‰) and low δ 15N values(4.7‰,6.0‰).B group,only one pig,has the highest δ 13C value(-10.6‰) and mediate δ 15N value(6.4‰).As for the C group,also only one pig,low δ 13C value(-19.0‰) and the highest δ 15N value(9.1‰) are observed.Previous studies on the stable isotopes from modern or ancient wild boars' bones have suggested that C3 plants are predominated in their diets and that their δ 15N values are close to those in herbivores and far from those in carnivores.Based on the comparison with the isotope values from humans,the wild boars and the domestic pigs from Xipo Site in Henan 6000―5500 years ago and Kangjia Site in Shaanxi 4500―4000 years ago,we conclude that A pig group belongs to wild boars while B and C groups can be attributed to domesticated pigs.

Chromosome-Level Reference Genome and Population Genomic Analysis Provide Insights into the Evolution and Improvement of Domesticated Mulberry (Morns alba)

Mulberry(Morns spp.)is the sole plant consumed by the domesticated silkworm.However,the genome of domesticated mulberry has not yet been sequenced,and the ploidy level of this species remains unclear.Here,we report a high-quality,chromosome-level domesticated mulberry(Morus alba)genome.Analysis of genomic data and karyotype analyses confirmed that M.alba is a diploid with 28 chromosomes(2/7=2x=28).Population genomic analysis based on resequencing of 134 mulberry accessions classified domesticated mulberry into three geographical groups,namely,Taihu Basin of southeastern China(Hu mulberry),northern and southwestern China,and Japan.Hu mulberry had the lowest nucleotide diversity among these accessions and demonstrated obvious signatures of selection associated with environmental adaptation.Further phylogenetic analysis supports a previous proposal that multiple domesticated mulberry accessions previously classified as different species actually belong to one species.This study expands our understanding of genome evolution of the genus Morus and population structure of domesticated mulberry,which would facilitate mulberry breeding and improvement.

Genome-wide association study of grain micronutrient concentrations in bread wheat

Bread wheat(Triticum aestivum)is a staple food crop worldwide.The genetic dissection of important nutrient traits is essential for the biofortification of wheat to meet the nutritional needs of the world's growing population.Here,45,298 single-nucleotide polymorphisms(SNPs)from 55K chip arrays were used to genotype a panel of 768 wheat cultivars,and a total of 154 quantitative trait loci(QTLs)were detected for eight traits under three environments by genome-wide association study(GWAS).Three QTLs(qMn-3B.1,qFe-3B.4,and qSe-3B.1/qFe-3B.6)detected repeatedly under different environments or traits were subjected to subsequent analyses based on linkage disequilibrium decay and the P-values of significant SNPs.Significant SNPs in the three QTL regions formed six haplotypes for qMn-3B.1,three haplotypes for qFe-3B.4,and three haplotypes for qSe-3B.1/qFe-3B.6.Phenotypic analysis revealed significant differences among haplotypes.These results indicated that the concentrations of several nutrient elements have been modified during the domestication of landraces to modern wheat.Based on the QTL regions,we identified 15 high-confidence genes,eight of which were stably expressed in different tissues and/or developmental stages.TraesCS3B02G046100 in qMn-3B.1 and TraesCS3B02G199500 in qSe-3B.1/qFe-3B.6 were both inferred to interact with metal ions according to the Gene Ontology(GO)analysis.TraesCS3B02G199000,which belongs to qSe-3B.1/qFe-3B.6,was determined to be a member of the WRKY gene family.Overall,this study provides several reliable QTLs that may significantly affect the concentrations of nutrient elements in wheat grain,and this information will facilitate the breeding of wheat cultivars with improved grain properties.

Significant genomic introgression from grey junglefowl(Gallus sonneratii)to domestic chickens(Gallus gallus domesticus)

Background Chicken is one of the most numerous and widely distributed species around the world,and many studies support the multiple ancestral origins of domestic chickens.The research regarding the yellow skin phenotype in domestic chickens(regulated by BCO2)likely originating from the grey junglefowl serves as crucial evidence for demonstrating the multiple origins of chickens.However,beyond the BCO2 gene region,much remains unknown about the introgression from the grey junglefowl into domestic chickens.Therefore,in this study,based on wholegenome data of 149 samples including 4 species of wild junglefowls and 13 local domestic chicken breeds,we explored the introgression events from the grey junglefowl to domestic chickens.Results We successfully detected introgression regions besides BCO2,including two associated with growth trait(IGFBP2 and TKT),one associated with angiogenesis(TIMP3)and two members of the heat shock protein family(HSPB2 and CRYAB).Our findings suggest that the introgression from the grey junglefowl may impact the growth performance of chickens.Furthermore,we revealed introgression events from grey junglefowl at the BCO2 region in multiple domestic chicken breeds,indicating a phenomenon where the yellow skin phenotype likely underwent strong selection and was retained.Additionally,our haplotype analysis shed light on BCO2 introgression event from different sources of grey junglefowl into domestic chickens,possibly suggesting multiple genetic flows between the grey junglefowl and domestic chickens.Conclusions In summary,our findings provide evidences of the grey junglefowl contributing to the genetic diversity of domestic chickens,laying the foundation for a deeper understanding of the genetic composition within domestic chickens,and offering new perspectives on the impact of introgression on domestic chickens.

Genetic analyses of ancient tea trees provide insights into the breeding history and dissemination of Chinese Assam tea(Camellia sinensis var.assamica)

Chinese Assam tea(Camellia sinensis var.assamica)is an important tea crop with a long history of cultivation in Yunnan,China.Despite its potential value as a genetic resource,its genetic diversity and domestication/breeding history remain unclear.To address this issue,we genotyped 469 ancient tea plant trees representing 26 C.sinensis var.assamica populations,plus two of its wild relatives(six and three populations of C.taliensis and C.crassicolumna,respectively)using 16 nuclear microsatellite loci.Results showed that Chinese Assam tea has a relatively high,but comparatively lower gene diversity(H_(S)=0.638)than the wild relative C.crassicolumna(H_S=0.658).Clustering in STRUCTURE indicated that Chinese Assam tea and its two wild relatives formed distinct genetic groups,with considerable interspecific introgression.The Chinese Assam tea accessions clustered into three gene pools,corresponding well with their geographic distribution.However,New Hybrids analysis indicated that 68.48%of ancient Chinese Assam tea plants from Xishuangbanna were genetic intermediates between the Puer and Lincang gene pools.In addition,10%of the ancient Chinese Assam tea individuals were found to be hybrids between Chinese Assam tea and C.taliensis.Our results suggest that Chinese Assam tea was domesticated separately in three gene pools(Puer,Lincang and Xishuangbanna)in the Mekong River valley and that the hybrids were subsequently selected during the domestication process.Although the domestication history of Chinese Assam tea in southwestern Yunnan remains complex,our results will help to identify valuable genetic resources that may be useful in future tea breeding programs.

Analysis of radiation diffusion of COVID-19 driven by social attributes

This paper first estimated the infectious capacity of COVID-19 based on the time series evolution data of confirmed cases in multiple countries. Then, a method to infer the cross-regional spread speed of COVID-19 was introduced in this paper, which took the gross domestic product(GDP) of each region as one of the factors that affect the spread speed of COVID-19 and studied the relationship between the GDP and the infection density of each region(China's Mainland, the United States, and EU countries). In addition, the geographic distance between regions was also considered in this method and the effect of geographic distance on the spread speed of COVID-19 was studied. Studies have shown that the probability of mutual infection of these two regions decreases with increasing geographic distance. Therefore, this paper proposed an epidemic disease spread index based on GDP and geographic distance to quantify the spread speed of COVID-19 in a region. The analysis results showed a strong correlation between the epidemic disease spread index in a region and the number of confirmed cases. This finding provides reasonable suggestions for the control of epidemics. Strengthening the control measures in regions with higher epidemic disease spread index can effectively control the spread of epidemics.

The wheat sucrose synthase gene TaSus1 is a determinant of grain number per spike

Some haplotypes of the sucrose synthase gene TaSus1 are associated with thousand-grain weight(TGW)in wheat(Triticum aestivum L.).However,no mutations have been identified within the gene to test this association.The effects of TaSus1 on grain number per spike(GNS)also are largely unknown.Our previous genome-wide association study identified TaSus-A1 as a candidate gene controlling fertile spikelet number per spike(FSN).In the present study,we generated two independent mutants for the three TaSus1 homoeologs by CRISPR/Cas9-mediated genome editing.The triple mutants displayed lower FSN,GNS,grain number per spikelet(GNST),and TGW than wild-type plants.In 306 hexaploid wheat accessions,two single-nucleotide polymorphisms in TaSus-A1 contributed differently to GNS.Introgression of the two alleles into a wheat genetic background confirmed their effects.The alleles differed in geographical distribution among the accessions.