四川常羽乌骨鸡群体遗传多样性分析

利用选自家禽基因组的10个微卫星标记,对四川常羽乌骨鸡5个群体(四川山地乌骨鸡白羽系、黑羽系;黄忠山地乌骨鸡;黄忠山地乌骨鸡绿壳蛋系;草科乌骨鸡)的遗传多样性进行了检测,计算了各群体的群体杂合度、群体间遗传距离,并根据遗传距离进行了聚类分析。结果表明所选择的微卫星标记在各群体中表现出较高的多态性;四川5个乌骨鸡群体遗传多样性比较丰富,群体平均杂合度为0.5383到0.6659;各群体间的遗传距离有一定的差异;聚类分析将5个群体聚为三类。     

基于全基因组SNP标记分析中国地方鸡品种的遗传多样性和种群结构

旨在对中国地方鸡品种的遗传多样性与种群结构进行分析。本研究使用Affymetrix Axiom 600K高密度鸡基因分型芯片对来自8个品种的157只地方鸡及233只商品鸡进行基因分型,以品种作为分组来计算各分组的观测杂合度、期望杂合度、次等位基因频率、近交系数及核苷酸多样性分析地方鸡群体的遗传多样性,利用进化树、主成分分析、群体结构、MDS等方法分析鸡群体的群体结构,基于状态同源(IBS)和群体分化系数(Fst)分析种群内部与种群之间的亲缘关系,利用长纯合片段(runs of homozygosity, ROH)估算得到基于ROH的近交系数。结果表明,各群体的观测杂合度均高于期望杂合度,次等位基因频率在0.175～0.236之间,近交系数在0.018～0.205之间,核苷酸多样性在0～6×10^-4之间,进化树与主成分分析表明品种间出现了明显的群体分化,地方鸡群体与商品鸡群的MDS分析发现我国地方鸡与商业肉鸡品种的遗传距离较近;IBS遗传距离在0.092 9～0.319 9之间;各品种成对Fst分析表明,群体间呈现中高分化程度(0.09～0.22);此次分析共得到了...     

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.     

A molecular analysis of the patterns of genetic diversity in local chickens from western Algeria in comparison with commercial lines and wild jungle fowls

The objectives of this study were to characterize the genetic variability of village chickens from three agro‐ecological regions of western Algeria: coastal (CT), inland plains (IP) and highlands (HL), to reveal any underlying population structure, and to evaluate potential genetic introgression from commercial lines into local populations. A set of 233 chickens was genotyped with a panel of 23 microsatellite markers. Geographical coordinates were individually recorded. Eight reference populations were included in the study to investigate potential gene flow: four highly selected commercial pure lines and four lines of French slow‐growing chickens. Two populations of wild red jungle fowls were also genotyped to compare the range of diversity between domestic and wild fowls. A genetic diversity analysis was conducted both within and between populations. Multivariate redundancy analyses were performed to assess the relative influence of geographical location among Algerian ecotypes. The results showed a high genetic variability within the Algerian population, with 184 alleles and a mean number of 8.09 alleles per locus. The values of heterozygosity (He and Ho) ranged from 0.55 to 0.62 in Algerian ecotypes and were smaller than values found in Jungle fowl populations and higher than values found in commercial populations. Although the structuring analysis of genotypes did not reveal clear subpopulations within Algerian ecotypes, the supervised approach using geographical data showed a significant (p < 0.01) differentiation between the three ecotypes which was mainly due to altitude. Thus, the genetic diversity of Algerian ecotypes may be under the influence of two factors with contradictory effects: the geographical location and climatic conditions may induce some differentiation, whereas the high level of exchanges and gene flow may suppress it. Evidence of gene flow between commercial and Algerian local populations was observed, which may be due to unrecorded crossing with commercial chickens. Chicken ecotypes from western Algeria are characterized by a high genetic diversity and must be safeguarded as an important reservoir of genetic diversity.     

Analysis of genetic diversity and the determination of relationships among western Mediterranean horse breeds using microsatellite markers

The distribution of genetic diversity and the genetic relationships among western Mediterranean horse breeds were investigated using microsatellite markers. The examined sample included seven Spanish and three Italian local horse breeds and populations, plus a Spanish Thoroughbred outgroup. The total number of animals examined was 682 (on average 62 animals per breed; range 20–122). The microsatellite marker set analysed provided 128 alleles (10.7 alleles per locus). Within‐breed genetic diversity was always high (>0.70), with breeds contributing about 8% of the total genetic variability. The mean molecular coancestry of the entire population examined was 0.205, Losino being the breed that contributed most. In addition to Nei's standard and Reynolds’ genetic distances, pair‐wise kinship distance and molecular coancestry were estimated. Remarkably similar breed rankings were obtained with all methods. Clustering analysis provided an accurate representation of the current genetic relationships among the breeds. Determining coancestry is useful for analysing genetic diversity distribution between and within breeds and provides a good framework for jointly analysing molecular markers and pedigree information. An integrated analysis was undertaken to obtain information on the population dynamics in western Mediterranean native horse populations, and to better determine conservation priorities.     

新昌宫廷黄鸡遗传多样性及遗传结构分析

为研究新昌宫廷黄鸡的遗传多样性及遗传结构,本实验利用STR分型技术对新昌宫廷黄鸡在26个微卫星位点上的遗传多样性进行检测,并分析其与仙居鸡、萧山鸡、龙游麻鸡、丝羽乌骨鸡和白耳黄鸡的遗传距离。结果显示:新昌宫廷黄鸡平均有效等位基因数为4.03个,多态信息含量变幅为0.41～0.85,平均为0.67,观察杂合度平均为0.60,期望杂合度平均为0.72,Shannon信息指数平均为1.50,表明宫廷黄鸡26个遗传位点具有高度多态性,即该群体具有较高的遗传多样性;基于遗传距离NJ系统进化树将6个不同群体聚为两大簇,其中白耳黄鸡单独成一簇,其他5个品种聚为一簇,与宫廷黄鸡遗传距离从小到大依次为丝羽乌骨鸡、龙游麻鸡、萧山鸡、仙居鸡、白耳黄鸡,基于FCA分析结果与遗传距离NJ系统进化树结果一致。     

安卡纯系肉鸡六个微卫星位点遗传多样性研究

安卡肉鸡是生长速度最快的有色羽肉鸡之一,具有适应性强、耐应激、饲料报酬高等特点。为了了解其群体遗传结构,实验利用6个微卫星标记对3个品系共150只个体进行遗传多样性检测。结果表明3个品系都具有较高的多态性,反映了群体基本的遗传特征,为安卡肉鸡的育种和利用提供了基本的研究数据。     

Genetic diversity of Bangladeshi native chickens based on complete sequence of mitochondrial DNA D-loop region

ABSTRACT

1. The aim of this study was to explore genetic diversity and possible origin of Bangladeshi (BD) native chickens. The complete mtDNA D-loop region was sequenced in 60 chickens representing five populations; naked neck, full feathered, Aseel, Hilly and autosomal dwarf. The 61 reference sequences representing different domestic chicken clades in China, India, Laos, Indonesia, Myanmar, and other Eurasian regions were included. The mtDNA D-loop sequence polymorphism and maternal origin of five BD populations were analysed.

2. A total of 35 polymorphic sites, and 21 haplotypes were detected in 60 mtDNA D-loop sequences. The haplotype and nucleotide diversity of the five populations were 0.921 ± 0.018 and 0.0061 ± 0.0019, respectively. Both mtDNA network and phylogenetic analysis indicated four clades (four haplogroups) in BD populations (21 haplotypes) along with 61 reference haplotypes. Clade E contained the most individuals (20) and haplotypes (11) of BD chickens, followed by clade D (17, 6), clade C (12, 2) and clade F (11, 2), respectively.

3. The higher number of unique haplotypes found in Yunnan, China, suggested that the origin of BD chickens was in this region. The haplotypes from different haplogroups were introduced in Bangladeshi chickens from India, China and Myanmar. The phylogenetic tree showed a close relationship of BD chickens with the clusters from India, China, Myanmar and Laos, and indicated the dispersion of BD chickens from these sources. The phylogenetic information revealed high genetic diversity of BD chickens because of their origin from different lineages with high genetic variation and distance, which was determined from four cluster and neighbour-joining trees.

4. In conclusion, BD populations had high genetic diversity. The mtDNA network profiles and phylogenetic trees showed multiple maternal origins of BD chickens from India, China, Myanmar and Laos.     

四川地方乌骨鸡种群遗传变异的微卫星DNA分析

利用10个微卫星标记，对四川不同地区5个乌骨鸡种群的等位基因频率、各群体的遗传杂合度、群体间的遗传距离等进行了分析，并根据遗传距离对这几个乌骨鸡种群进行了聚类分析。结果表明，各乌骨鸡群体的遗传多样性较为丰富，并具有较高的选择潜力。各乌骨鸡种群间有一定的遗传距离，UPGMA聚类分析表明，四川山地乌骨鸡黑羽系与川南山地乌骨鸡被聚为一类，草科鸡与旧院黑鸡被聚为一类。     

药用价值地方鸡种动态保种的研究

通过资源调查摸清我国10个药用价值地方鸡种的保存现状,发现金阳丝毛鸡已经濒临灭绝.其他9个药用价值地方鸡种均处于正常保种状态.通过筛选的27个多态性较好的微卫星标记,检测了我国9个药用价值地方鸡种的遗传多样性.利用等位基因频率计算了各群体的遗传参数、构建了聚类图,并进行了系统发生分析.根据调查结果及遗传多样性检测数据,分析的9个药用价值地方鸡种保存状态,并提出保护建议.     

Assessment of genetic diversity and conservation priority of Omani local chickens using microsatellite markers

Designing strategies for conservation and improvement livestock should be based on assessment of genetic characteristics of populations under consideration. In Oman, conservation programs for local livestock breeds have been started. The current study assessed the genetic diversity and conservation potential of local chickens from Oman. Twenty-nine microsatellite markers were analyzed in 158 birds from six agroecological zones: Batinah, Dhofar, North Hajar, East Hajar, Musandam, and East Coast. Overall, a total of 217 alleles were observed. Across populations, the average number of alleles per locus was 7.48 and ranged from 2 (MCW98 and MCW103) to 20 (LEI094). The mean expected heterozygosity (H _E) was 0.62. Average fixation index among populations (F _ST) was 0.034, indicating low population differentiation, while the mean global deficit of heterozygotes across populations (F _IT) was 0.159. Based on Nei’s genetic distance, a neighbor-joining tree was constructed for the populations, which clearly identified the Dhofar population as the most distant one of the Omani chicken populations. The analysis of conservation priorities identified Dhofar and Musandam populations as the ones that largely contribute to the maximal genetic diversity of the Omani chicken gene pool.     

太湖鸡资源群体遗传变异的检测

应用微卫星标记对江苏省无锡市祖代鸡场有限公司太湖鸡的保种群体进行了遗传变异的分析,计算了群体的杂和度(H)和多态信息含量(PIC)。研究结果表明:30个微卫星标记在太湖鸡保种群体的杂和度为0.504～0.858之间,平均杂和度为0.688,群体的遗传多样性丰富;其中24个微卫星标记在太湖鸡中多态信息含量为高度多态,可作为有效遗传标记用于太湖鸡保种群的遗传分析,而且各座位杂和度的高低与PIC值的大小体现了较高的一致性。本研究结果为太湖鸡开发利用研究提供了基础,也为太湖鸡的合理保护提供了科学根据。     

Genetic diversity and population structure analysis of eight local chicken breeds of Southern Xinjiang

ABSTRACT

1. The genetic diversity and population structure were studied for eight local chicken breeds, including Anjiyan (AN), Hetian Black (HH), Hetian Ma (HM), Aheqi (AH), Baicheng You (BC), Hejing (HJ), Tashkurghan (TS) and Ruoqiang (RQ), in the Southern Xinjiang region of China, using 20 microsatellite markers.

2. Total 336 alleles were obtained from all chicken breeds, with a mean of 16.8 alleles per locus. The polymorphism information content ranged from 0.444 to 0.911, with a mean of 0.729 and almost all of the loci showed significant deviation from Hardy-Weinberg standards. The observed and expected heterozygosity of the eight breeds ranged from 0.5 to 0.677 and from 0.656 to 0.774, with the lowest observed in the AN and the highest in BC breed. The average breed genetic diversity was 0.655 for AN and 0.766 for BC chickens.

3. According to the neighbour-joining (NJ) method, three main clusters were identified in the NJ phylogenetic tree with AN and RQ breeds in one clade, HH and HM breeds in the second clade and TS, HJ, AH and BC breeds in the third clade.

4. Based on STRUCTURE analysis, the most likely cluster number of all breeds was K = 4, whereby HH and HM breeds formed one cluster and AH, BC, HJ and TS formed another, and RQ, AN chicken formed their own distinct cluster. These results indicated that HH and HM breeds had similar genetic background, as did the breeds of AH, BC, HJ and TS. RQ, AN breed had unique genetic backgrounds, distinct from the other breeds. Genetic introgression was detected from AN to HH and HM.

5. The results of the current study can be used as baseline genetic information to implement effective conservation programs and to make better use of these local chicken breeds, especially for the AN, RQ and TS breeds.     

地方鸡种与隐性白羽鸡遗传变异的AFLP指纹

利用6对AFLP引物组合对我国12个地方鸡种和引进鸡种隐性白羽鸡进行了遗传检测,统计了每个引物组合在各个品种中检测到的多态性条带和特异性条带,计算了13个鸡种的遗传相似系数和遗传距离,并据此构建了UPGMA聚类关系图,分析了所研究鸡种的遗传关系.结果表明:6对AFLP引物组合在13个鸡种中共检测到290条多态性条带,平均每个引物组合产生48.3奈多态性标记,同时在每个品种群体中还检测到了数量不等的特异性条带,其中寿光鸡和东乡黑鸡最多,为9条,旧院黑鸡、兴义矮脚鸡和隐性白羽鸡最少,为1条.13个鸡种聚为4类,其中隐性白羽鸡单独聚为一类,鸡种间的遗传相似系数及聚类结果与各个鸡种的地理分布、现实状况相吻合,从而表明AFLP指纹用于我国地方鸡种的遗传多态性分析、品种鉴定及品种间亲缘关系分析是可行的.     

基于线粒体控制区的鸡不同杂交组合遗传多样性研究

旨在探讨鸡不同杂交组合线粒体控制区（mtDNA D-loop区）的遗传多样性和单倍型特性。选取固始鸡和隐性白羽鸡及其正、反交F1代、藏鸡以及F2代等6个群体共387个个体的mtDNA D-loop区进行测序,分析其遗传规律和单倍型特性,并与不同红色原鸡亚种进行聚类,分析其母系起源。结果显示,6个群体D-loop区全序列大小为1 231 bp,共检测到28个多态位点和1个C碱基缺失,共构成19种单倍型,分为A、B、C和E 4个单倍型群,其中,固始鸡和反交F1代主要为A、C单倍型,固始鸡A、C单倍型比例分别为53.42%和46.58%,反交F1代A、C单倍型比例分别为50.75%和49.25%;隐性白羽鸡、正交F1代和F2代优势单倍型均为E单倍型,占比分别为48.89%、48.84%和50.00%。6个鸡群体单倍型多样度（Hd）在0.496~0.729之间,核苷酸多样度（Pi）在0.003 40~0.005 41之间,Hd值和Pi值最大的均为正交F1代,其次为隐性白羽鸡和F2代,固始鸡和反交F1代群体遗传多样性接近。聚类分析显示,A、B单倍型群与滇南亚种交叉聚为一枝;E单倍型群与印度亚种交叉聚为一枝;C单倍型群与印度亚种、指名亚种、印尼亚种以及滇南亚种聚为一枝。结果提示,mtDNA D-loop区遵循严格的母系遗传,后代的遗传多样性和单倍型比例与其母本基本一致;我国家鸡群体具有多个红色原鸡母系起源,且主要起源于原鸡滇南亚种。     

应用系统进化方法评估徐海鸡遗传资源

利用简化基因组SNPs数据分析徐海鸡及周边地方鸡种遗传多样性,为徐海鸡的保护和利用提供支持.收集徐海鸡等13个地方鸡种血液样品,提取基因组DNA,应用简化基因组测序技术进行SNP分型,获取群体遗传学参数,并以邻接法、最大似然法、贝叶斯法构建系统进化树.结果显示:徐海鸡基因组SNPs观测杂合度为0.18,期望杂合度为0....     

利用微卫星遗传标记评估5个西藏牦牛群体遗传多样性及群体结构

【目的】 评估当前西藏主要牦牛群体遗传多样性，梳理不同地区群体间遗传结构，明确西藏5个牦牛群体（阿里牦牛、斯布牦牛、娘亚牦牛、类乌齐牦牛和帕里牦牛）的保种情况和种群间系统发育关系。【方法】 利用13个微卫星标记（SSR）对5个牦牛群体共计195个个体进行基因分型，并对各群体的等位基因数量、基因杂合度、多态信息含量及群体间遗传距离等遗传参数进行评估。【结果】 阿里牦牛群体等位基因数最多（6.43），类乌齐牦牛等位基因数最少（5.00）；观测杂合度范围为0.5311（娘亚牦牛）~0.5995（类乌齐牦牛）。各群体内偏离Hardy-Weinberg平衡的位点数为5（类乌齐牦牛）~9（阿里牦牛）个；群体内近交系数最高为0.172（阿里牦牛），且4个群体（阿里牦牛、娘亚牦牛、斯布牦牛和帕里牦牛）存在显著近交风险（P<0.05）。从遗传结构来看，所有群体间均为显著遗传分歧（P<0.05），STRUCTURE分析结果显示，5个牦牛群体划分为3个簇，其中阿里牦牛较其他牦牛群体具有更为丰富的遗传背景。系统发育树结果表明，不同群体间系统发育关系相对独立，且与种群栖息地分布不一致。主坐标分析（PCoA）结果显示，不同群体间部分个体存在较近亲缘关系，表明不同群体间存在遗传物质交流。【结论】 5个西藏牦牛群体具有丰富的遗传多样性水平，且种群系统发育关系相对独立，但多数群体存在群体事件风险。本研究不仅有助于明确西藏牦牛地方种群遗传多样性水平，同时可为今后的保种策略提升提供理论参考。     

The multiple burdens of zoonotic disease and an ecohealth approach to their assessment

Individual interviews were conducted in 137 households using semi-structured questionnaires to determine the influence of socioeconomic factors on production constraints faced by indigenous chicken producers in the rural areas of South Africa. The major constraints to village chicken production were mortality (95 % of the households) followed by feed shortage (85 %) and low chicken sales (72 %). The logistic regression model showed that households that owned imported/crossbred chickens practiced extensive production system without housing structures and did not have vaccines were more likely to experience high levels of chicken mortality. Poor and youth-headed households with no supplements and vaccines had high probability of Newcastle disease. The probability of a household to experience chicken feed shortage was lower in households that owned indigenous chickens than those that owned imported/crossbred chickens (odds ratio, 11.68; 95 % confidence interval, 1.19–27.44). Youth-headed households that had small flocks and no access to veterinary services were not likely to sell chickens. It was concluded that gender, age, wealth status, production system, chicken flock size, type of chicken breed owned, accessibility of veterinary services, availability of supplements, vaccines and shelter influence village chicken farmer’s production constraints such as feed availability, chicken mortality, prevalence of diseases and chicken sales.     

利用微卫星标记分析江苏三个地方鸡品种的遗传多样性

利用30个微卫星DNA标记对3个江苏地方鸡品种进行遗传多样性分析，通过计算等位基因频率、多态信息含量、平均杂合度、有效等位基因数和遗传距离，评估各品种内遗传变异和各品种间遗传相关。结果表明：江苏的3个品种在30个微卫星上共发现196个等位基因，其中96个等位基因为三个品种共有，47个等位基因为各品种所特有；3个地方鸡品种的平均杂合度：狼山鸡为0．655，鹿苑鸡为0．681，溧阳鸡为0．687；狼山鸡与溧阳鸡的遗传距离较小，而两鸡与鹿苑鸡的遗传距离较远。     

Marker-based estimates of between and within population kinships for the conservation of genetic diversity

In this article coefficients of kinship between and within populations are proposed as a tool to assess genetic diversity for conservation of genetic variation. However, pedigree-based kinships are often not available, especially between populations. A method of estimation of kinship from genetic marker data was applied to simulated data from random breeding populations in order to study the suitability of this method for livestock conservation plans. Average coefficients of kinship between populations can be estimated with low Mean Square Error of Prediction, although a bias will occur from alleles that are alike in state in the founder population. The bias is similar for all populations, so the ranking of populations will not be affected. Possible ways of diminishing this bias are discussed. The estimation of kinships between individuals is imprecise unless the number of marker loci is large (> 200). However, it allows distinction between highly related animals (full sibs, half sibs and equivalent relations) and animals that are not directly related if about 30–50 polymorphic marker genes are used. The marker-based estimates of kinship coefficients yielded higher correlations than genetic distance measures with pedigree-based kinships and thus to this measure of genetic diversity, although correlations were high overall. The relation between coefficients of kinship and genetic distances are discussed. Kinship-based diversity measures conserve the founder population allele frequencies, whereas genetic distances will conserve populations in which allele frequencies are the most different. Marker-based kinship estimates can be used for the selection of breeds and individuals as contributors to a genetic conservation programme.