Genetic diversity and structure in Asian native goat analyzed by newly developed SNP markers

In the current study, a total of 65 single nucleotide polymorphisms (SNPs) within the intron region were developed in goat (Capra hircus) by utilizing genomic information of cattle and sheep due to poor available genomic information on goat. Using these markers, we carried out genetic diversity and structure analyses for 10 Asian goat populations. The phylogenetic tree and principal components analysis showed good correspondence between clustered populations and their geographic locations. The STRUCTURE software analysis illustrated six divergent genetic structures among 10 populations. Myanmar and Cambodia populations showed high admixture patterns with different ancestry, suggesting genetic introgression into native goat populations. We also investigated the correlation between genetic diversity and geographic distance from a domestication center. This result showed a decreasing trend of genetic diversity according to the distance (P = 0.014). This result supported common consensus that western Asia is one of the centers of origin for modern Asian domestic goat.     

Novel variants within the coding regions of the Slc11A1 gene identified in Bos taurus and Bos indicus breeds

Although in the cow the genetic resistance to brucellosis has been previously attributed to the Slc11A1 gene encoding Nramp1 protein, none of the mutations described to date seems to be the cause. To be able to associate another polymorphism of the gene to brucellosis resistance, we characterized the gene and identified in different breeds of Bos taurus and Bos indicus, six new variants among a total of 11 single nucleotide mutations, of which five occurred in the coding sequence (three are missense mutations), one in the promoter region and five in introns. The allelic and genotypic frequencies calculated revealed differences (p < 0.05) among the breeds studied.     

Allele frequencies of gene polymorphisms related to economic traits in Bos taurus and Bos indicus cattle breeds

Allele frequencies of 10 representative polymorphisms for beef and milk traits were investigated for a total of 240 animals from Bos taurus and Bos indicus breeds, including two Japanese groups (Japanese Black and Japanese Brown), two East Asian groups (Korean and Mongolian), three European groups (Holstein, Angus and Hereford) and a Bos indicus group in South Asia (Myanmar, Laos and Cambodia). The Japanese Black revealed unique genetic construction in GH, FASN and SREBP‐1 and the other Asian populations show intermediate frequencies between European and Japanese populations. The Bos indicus group showed low favorable allele frequencies in most of the genes. The study showed the variability and distribution of 10 genes affecting economic traits among world representative cattle breeds. The genetic information would contribute to elucidating the genetic background for worldwide cattle breeds and the possibility of improvement using the markers.     

十个歪头菜居群遗传多样性分析

采用ISSR分子标记对10个歪头菜自然居群的104个样本进行遗传多样性分析,筛选的10条ISSR引物共扩增出115个位点,其中多态性位点110个。在物种水平上多态性比率(PPB)为95.65%,在居群内多态位点比率为24.35%~49.70%。POPGENE分析结果显示,物种水平上Nei’s 基因多样性(H)为0.2632,Shannon’s遗传多样性信息指数(I)为0.4046,基因流(Nm)为0.4553,基因分化度(Gst)为0.5283,AMOVA分析居群间遗传分化程度为50.51%。研究表明,10个采样点的歪头菜在物种水平上具有较高的遗传多样性,但在居群之间已经出现了一定程度的遗传分化,且居群间的遗传分化程度高于居群内的分化程度。同时,证明了环境压力大小对于遗传多样性的高低具有选择作用,环境压力小的烟台和环境压力大的合作地区具有较高的遗传多样性,但环境压力介于二者之间的地区遗传多样性水平相对较低。本研究结果不仅对于了解歪头菜遗传进化和其生长地的环境的关系具有重要的参考价值,对合理利用歪头菜遗传资源及育种还具有非常重要的作用。     

亚丁牦牛和拉日马牦牛遗传多样性及遗传结构分析

亚丁牦牛和拉日马牦牛均为肉乳兼用型优良地方牦牛资源,本研究旨在探究亚丁牦牛和拉日马牦牛的遗传多样性及各牦牛群体间的亲缘关系,对亚丁牦牛、拉日马牦牛以及其他7个地方牦牛群体(九龙牦牛、麦洼牦牛、金川牦牛、昌台牦牛、中甸牦牛、玉树牦牛、类乌齐牦牛)进行RAD简化基因组测序,基于检测到的SNP信息计算遗传统计量.结果表明,亚...     

野牛草种质基于SRAP标记的遗传多样性研究

野牛草(Buchloe dactyloides)是一种低养护的暖季型草坪草,本研究利用相关序列扩增多态性（SRAP）标记对来自美国、加拿大和日本的31份野牛草材料进行遗传多样性分析。结果表明,用19对引物组合共扩增出271条多态性条带,多态性位点百分率为86.86%,材料间的遗传相似系数(GS)为0.586 5~0.916 7,平均GS值为0.669 1。两个材料在不同的引物组合扩增下,分别出现特异性条带和缺失性条带,这些条带可用于野牛草基因型的鉴定。非加权成对算术平均法（UPGMA）聚类分析和主成分分析结果表明,供试材料可聚成两类,而相同地理来源的材料并未聚为一类。     

Genetic diversity of Forest and Savannah chicken populations of Ghana as estimated by microsatellite markers

The characterization of indigenous animal genetic resources is a requisite step in providing needed information for the conservation of useful genotypes against future needs. Thus, in this study, 22 microsatellite markers were used to genotype 114 local chickens from the Forest (n = 59) and Savannah (n = 55) eco‐zones of Ghana and the results compared to those of the ancestral red junglefowl (n = 15) and two European commercial chicken populations – a broiler (n = 25) and white leghorn (n = 25). A total of 171 alleles were observed, with an average of 7.8 alleles per locus. The local Ghanaian chickens showed higher diversity in terms of the observed number of alleles per locus (6.6) and observed heterozygosity (0.568) compared with the combined control populations (6.0 and 0.458, respectively). However, Wright's F‐statistics revealed negligible genetic differentiation (F_ST) in local Ghanaian chicken populations. In addition, 65% of the Savannah chickens were inferred to be more likely from the Forest, suggesting a south‐north dispersal of chickens from their probable original location in the Forest zone to the Savannah areas. It is concluded that the Forest and Savannah chickens of Ghana are a single, randomly mating unselected population, characterized by high genetic diversity and constitute a valuable resource for conservation and improvement.     

不同产地麦冬遗传多样性的SRAP分析

本研究使用SRAP分子标记技术对48份不同产地的麦冬进行遗传多样性分析,筛选出11对有效引物组合。11对引物组合共扩增出621条清晰、可辨认条带,平均每对引物扩增出56.45条带纹,多态性条带为621条,多态性位点百分率为100%,遗传相似系数（GS）范围为 0.058 4～0.936 7,平均为0.497 5,说明供试材料具有丰富的遗传多样性。对所有材料聚类分析发现,在遗传距离0.81处可将材料分为六大类群,部分来自同一地理位置的材料可聚为一类     

42份紫花苜蓿种质资源遗传多样性的SSR分析

为了补充现有苜蓿(Medicago sativa)种质资源的遗传多样性信息,采用SSR分子标记技术对1份野生紫花苜蓿种质和41份栽培紫花苜蓿品种的遗传多样性进行了研究。15对引物在供试苜蓿材料中共获得231条扩增带,其中163条具有多态性。引物的多态位点百分率、Nei’s基因多样性指数和Shannon信息指数的平均值分别为71.55%、0.210 0和0.326 3。供试材料间的相似系数介于0.641~0.913,平均为0.791,栽培品种间的平均相似系数相对较大,野生种质资源与栽培品种间的平均相似系数相对较小。聚类分析表明,供试材料在相似系数0.778处可聚为五大类,单独聚为类的陇东野生紫花苜蓿、CW 200和CW 787都表现出了与其他材料间较远的亲缘关系。基于主成分分析图,可把供试材料分为四大类,其中第Ⅰ、Ⅱ类与第Ⅲ、Ⅳ类材料间的亲缘关系较远。综上,供试苜蓿种质资源具有较丰富的遗传多样性,部分种质资源表现出了相对独立的遗传特性。     

鱼腥草不同地理群体遗传结构与变异的研究

采用SRAP分子标记技术对湖南省怀化地区16个野生鱼腥草群体的遗传特征进行了分析。结果表明,16个鱼腥草群体的多态位点比例(PPB)为53.66%~85.35%,Nei基因多样性指数(h)为0.07~0.23,Shannon表型信息指数(I)为0.10~0.34,说明在鱼腥草群体水平上有相对较高的遗传变异;群体间的基因分化系数(Gst)为0.51,表明大部分的遗传变异均存在于群体间,同时群体内具有一定频率的基因流(Nm=0.326)。UPGMA聚类分析表明,16个群体在遗传距离为0.5处分为五大类群,并且有一定的地缘关系。相关性分析表明,虽然16个鱼腥草群体的遗传结构与生境因子相关均不显著,但基因分化系数(Gst)和基因流(Nm)随海拔的增加有上升而随着纬度和经度的增加有下降的趋势。     

Genetic correlations between body weight,scrotal circumference and visual evaluation scores in Bos indicus cattle

The objective was to estimate genetic correlations between body weight (BW), scrotal circumference and visual evaluation scores of body conformation measured at standard ages in Guzerat cattle. All measurements were performed at 205 (weaning age), 365, 450 and 550 days of age; for BW, two additional measurements (at birth and 120 days of age) were realized. The data utilized in this study were retrieved from a database of the Brazilian Association of Zebu Breeders that contained information of registered Guzerat animals born between 1970 and 2013. Genetic parameters were estimated in bi‐trait analyses by using Bayesian inference. Genetic correlations between BW at 205 and 450 days of age with other traits were high and positive, whereas the correlations between visual evaluation scores with other traits were moderate. Based on correlations herein obtained, we conclude that selection based on BW results in increased visual scores and scrotal circumference, leading to improvements in productive performance and animals with best body conformation.     

Molecular characterization and SNP identification in HSPB6 gene in Karan Fries (Bos taurus x Bos indicus) cattle

Tropical Animal Health and Production - Heat shock proteins (HSPs) act as molecular chaperones which are preferentially transcribed in response to severe perturbations of the cellular homeostasis...     

Genetic structure and differentiation of 12 African Bos indicus and Bos taurus cattle breeds, inferred from protein and microsatellite polymorphisms

Level of genetic differentiation, gene flow and genetic structuring of nine Bos indicus and three Bos taurus cattle breeds in Cameroon and Nigeria were estimated using the genetic information from 16 microsatellite, five blood protein and seven milk protein markers. The global heterozygote deficit across all populations (F_it) amounted to 11.7% (p < 0.001). The overall significant (p < 0.001) deficit of heterozygotes because of inbreeding within breeds (F_is) amounted to 6.1%. The breeds were moderately differentiated (F_st = 6%, p < 0.001) with all loci except CSN1S2 contributing significantly to the F_st value. The 12 populations belong to two genetic clusters, a zebu and a taurine cluster. While inferred sub‐clusters within the taurine group corresponded extremely well to predefined breed categorizations, no real sub‐clusters, corresponding to predefined breeds, existed within the zebu cluster. With the application of prior population information, cluster analysis achieved posterior probabilities from 0.962 to 0.994 of correctly assigning individuals to their rightful populations. High gene flow was evident between the zebu populations. Positive and negative implications of the observed genetic structure of the breeds on their development, improvement and conservation are discussed. The study shows that the breeds are threatened by uncontrolled breeding and therefore are at risk to become genetically uniform in the future. This situation can be avoided by putting in place effective breeding and management measures aimed at limiting uncontrolled mating between the breeds and to preserve special characteristics, genetic as well as breed biodiversity. The first step towards realizing these goals might be to geographically demarcate the breeds.     

Genetic diversity and conservation of South African indigenous chicken populations

In this study, we compare the level and distribution of genetic variation between South African conserved and village chicken populations using microsatellite markers. In addition, diversity in South African chickens was compared to that of a reference data set consisting of other African and purebred commercial lines. Three chicken populations Venda, Ovambo and Eastern Cape and four conserved flocks of the Venda, Ovambo, Naked Neck and Potchefstroom Koekoek from the Poultry Breeding Resource Unit of the Agricultural Research Council were genotyped at 29 autosomal microsatellite loci. All markers were polymorphic. Village chicken populations were more diverse than conservation flocks. structure software was used to cluster individuals to a predefined number of 2 ≤ K ≤ 6 clusters. The most probable clustering was found at K = 5 (95% identical runs). At this level of differentiation, the four conservation flocks separated as four independent clusters, while the three village chicken populations together formed another cluster. Thus, cluster analysis indicated a clear subdivision of each of the conservation flocks that were different from the three village chicken populations. The contribution of each South African chicken populations to the total diversity of the chickens studied was determined by calculating the optimal core set contributions based on Marker estimated kinship. Safe set analysis was carried out using bootstrapped kinship values calculated to relate the added genetic diversity of seven South African chicken populations to a set of reference populations consisting of other African and purebred commercial broiler and layer chickens. In both core set and the safe set analyses, village chicken populations scored slightly higher to the reference set compared to conservation flocks. Overall, the present study demonstrated that the conservation flocks of South African chickens displayed considerable genetic variability that is different from that of the assumed founder populations (village chickens).     

钝裂银莲花不同居群遗传多样性的ISSR分析

本研究采用ISSR分子标记技术分析了甘肃省4个地区(合作、碌曲、阿万仓和阿孜)钝裂银莲花的11个居群的遗传多样性水平和遗传结构。结果表明,13个引物共扩增出701条带,其中392条具有多态性,多态位点百分率为55.92%。在物种水平上,Shannon多样性指数(I)为0.372,Nei基因多样性指数(H)为0.250;Nei的基因分化系数Gst和AMOVA分析表明钝裂银莲花居群遗传分化大部分存在于居群间。在居群水平上,I为0.183,H为0.114,可见钝裂银莲花居群具有较高的遗传多样性。依据Nei的遗传距离对不同居群进行UPGMA聚类,聚类结果为合作居群为一类,碌曲和阿万仓居群为一类,阿孜为一类。居群遗传多样性与环境因子间的相关性分析表明,遗传多样性水平与海拔、含水量、有效磷和经纬度之间没有相关性,而与降水量之间显著负相关。     

Differences in genetic structure assessed using Y‐chromosome and mitochondrial DNA markers do not shape the contributions to diversity in African sires

Up to 173 African sires belonging to 11 different subpopulations representative of four cattle groups were analysed for six Y‐specific microsatellite loci and a mitochondrial DNA fragment. Differences in Y‐chromosome and mtDNA haplotype structuring were assessed. In addition, the effect of such structuring on contributions to total genetic diversity was assessed. Thirty‐five Y‐chromosome and 71 mtDNA haplotypes were identified. Most Y‐chromosomes analysed (73.4%) were of zebu origin (11 haplotypes). Twenty‐two Y‐haplotypes (44 samples) belonged to the African taurine subfamily Y2a. All mtDNA haplotypes belonged to the “African” taurine T1 haplogroup with 16 samples and nine haplotypes belonging to a recently identified subhaplogroup (T1e). Median‐joining networks showed that Y‐chromosome phylogenies were highly reticulated with clear separation between zebu and taurine clusters. Mitochondrial haplotypes showed a clear star‐like shape with small number of mutations separating haplotypes. Mitochondrial‐based F_ST‐statistics computed between cattle groups tended to be statistically non‐significant (p > .05). Most F_ST values computed among groups and subpopulations using Y‐chromosome markers were statistically significant. AMOVA confirmed that divergence between cattle groups was only significant for Y‐chromosome markers (Φ_CT = 0.209). At the mitochondrial level, African sires resembled an undifferentiated population with individuals explaining 94.3% of the total variance. Whatever the markers considered, the highest contributions to total Nei's gene diversity and allelic richness were found in West African cattle. Genetic structuring had no effect on patterns of contributions to diversity.     

Genetic analysis of Mexican Criollo cattle populations

The objective of this study was to evaluate the genetic structure of Mexican Criollo cattle populations using microsatellite genetic markers. DNA samples were collected from 168 animals from four Mexican Criollo cattle populations, geographically isolated in remote areas of Sierra Madre Occidental (West Highlands). Also were included samples from two breeds with Iberian origin: the fighting bull (n = 24) and the milking central American Criollo (n = 24) and one Asiatic breed: Guzerat (n = 32). Genetic analysis consisted of the estimation of the genetic diversity in each population by the allele number and the average expected heterozygosity found in nine microsatellite loci. Furthermore, genetic relationships among the populations were defined by their genetic distances. Our data shows that Mexican cattle populations have a relatively high level of genetic diversity based either on the mean number of alleles (10.2-13.6) and on the expected heterozygosity (0.71-0.85). The degree of observed homozygosity within the Criollo populations was remarkable and probably caused by inbreeding (reduced effective population size) possibly due to reproductive structure within populations. Our data shows that considerable genetic differentiation has been occurred among the Criollo cattle populations in different regions of Mexico.     

利用微卫星标记分析乌骨大骨鸡的遗传多样性

利用微卫星标记分析了乌骨大骨鸡的遗传多样性和遗传结构,筛选了鸡基因组7条染色体上的7个微卫星标记位点,随机选取24羽乌骨大骨鸡个体,进行多态性检测,共检测到23个等位基因,每个座位等位基因数目从2个到5个不等,平均等位基因数为3.3个。该群体平均多态信息含量和平均杂合度分别为0.660 3和0.717 6。结果表明乌骨大骨鸡属多态性较丰富的群体。