分子标记与地方猪品种的遗传多样性研究

分子标记已成为目前家畜遗传多样性研究的主要工具.本文简要综述了多种分子标记(RFLPs, mt-DNA, RAPD, DNA指纹图谱,微卫星DNA,AFLP,SNPs)的检测方法及其在地方猪品种遗传变异和遗传关系检测分析中的应用,为类似研究提供参考材料.     

中国地方猪种线粒体基因组遗传多样性及其系统发育分析

为从分子水平上探究中国地方猪种遗传多样性和分类地位,本试验采用生物信息学方法比较了6个类型共22个中国地方猪种的线粒体基因组全序列,分析了其多态性,并构建了6个类型猪种线粒体D-loop区单倍型的网络中介图以及基于线粒体D-loop序列、Cytb基因、完整编码区序列的系统进化树。结果表明,6个类型22个猪种中共检测到了144个多态位点,22种单倍型,说明地方猪种具有丰富的遗传多样性;地方猪线粒体基因组序列中核苷酸变异以转换为主,且Ti/Tv大于转换/颠换比临界值（2.0）,变异位点均符合中性突变。6个类型猪种间遗传距离均较小,且有共享单倍型。系统进化树结果表明,6种类型地方猪种主要聚为两个支系。表明线粒体D-loop序列及Cytb基因均可作为研究种内系统发育、起源进化的分子标记。     

中国地方猪遗传多样性研究进展

我国拥有丰富的猪品种和遗传资源,研究其遗传多样性不仅有利于科学、有效地开展地方猪遗传资源的保护工作,同时对猪的分类鉴定、选育提高、开发利用等具有重要意义。本文对2018年以来中国地方猪种基于微卫星位点、mtDNA、SNP芯片、简化基因组测序和全基因组重测序的遗传多样性研究进行综述,以期为中国地方猪种的遗传资源保护、开发和利用提供参考。     

分子标记与地方猪品种的遗传多样性研究

分子标记已成为目前家畜遗传多样性研究的主要工具。本文简要综述了多种分子标记(RFLPs，nat-DNA，RAPD，DNA指纹图谱，微卫星DNA，AFLP，SNPs)的检测方法及其在地方猪品种遗传变异和遗传关系检测分析中的应用，为类似研究提供参考材料。     

微卫星标记分析福建地方品种猪的遗传多样性

采用8个微卫星座位对福建省5个地方猪种(槐猪、官庄花猪、莆田黑猪、闽北花猪、武夷黑猪)的遗传结构进行了分析,计算了遗传杂合度、有效等位基因数、多态信息含量、Nei氏标准遗传距离。结果表明:8个位点均为高度多态位点;5个猪种群体内的遗传多样性比较高,8个微卫星位点平均杂合度介于0.7006～0.7760之间;多态信息含量在0.6917～0.7609之间;槐猪与武夷黑猪的遗传距离最小0.5531,官庄花猪与闽北花猪的遗传距离最大0.8618。     

中国地方猪种血液蛋白遗传多样性的研究

采用不连续垂直板聚丙烯酰胺凝胶电泳检测了38个地方猪种和3个外来猪种的10个血液蛋白座位,并计算了遗传杂合度(h)、F-,统计量,用probabilitytest进行Hardy-Weinberg平衡符合度的检验,以及用Nei氏标准遗传距离DS、Nei氏遗传距离DA、UPGMA和NJ分析了猪群间的遗传关系。结果表明,Alb为单态,Pa-2、Pa-1、Po-1、Po-2、Cp、Am、Akp和Hpx9个血液蛋白座位分别受2、2、2、3、3、3、4和7个等位基因所调控;41个猪种的平均遗传杂合度范围为0.230～0.447;一些座位在某些种群中处于不平衡状态(P<0.05)或极不平衡状态(P<0.01);中国地方猪种间的遗传距离差异较大(P<0.011≤Ds≤0.616;0.014≤DA≤0.343);聚类结果将38个地方猪种分为3类。     

猪品种遗传多样性的研究进展

从猪品种的体型外貌、染色体带型、血型和蛋白质以及DNA分子水平等几个方面对猪的遗传多样性进行论述 ,并对遗传多样性的度量参数作了分析。认为猪种遗传多样性的研究是保种和利用的理论基础 ,从形态到DNA分子水平对猪品种遗传多样性的研究在遗传资源大量流失的今天具有重要意义。     

中国地方猪种血液蛋白遗传多样性的研究

采用不连续垂直板聚丙烯酰胺凝胶电泳检测了58个地方猪种和5个外来猪种的10个血液蛋白座位,并计算了遗传杂台度（h）、F-统计量．用probabilitytest进行Hardy Weinberg平衡符合度的检验,以及用Nei氏标准遗传距离Ds、Nei氏遗传距离Da、UPGMA和NJ分析了猪群间的遗传关系。结果表明．Alb为单态,Pa-2、Pa-1、Po-1、Po-2、Cp,Am、Akp和Hpx9个血液蛋白座位分别受2,2．2、5、5、5、4和7个等位基因所调控;41个猪种的平均遗传杂合疫范围为0．250～0．447;一些座位在某些种群中处于不平衡状态（P〈0．05）或极不平衡状态（P〈0．01）;中国地方猪种间的遗传距离差异较大（0．011≤DS≤0．616;0．014≤DA≤0．545）;聚类结果将58个地方猪种分为5类。     

中国地方品种牛血液同工酶遗传多样性研究进展

本文综述了中国地方黄牛和水牛品种的血液同工酶遗传多样性的研究现状及其在牛遗传育种中的应用。     

我国地方猪品种-乌金猪的生理特性研究

对生长在海拔1172.5m的云南省威信县的乌金猪进行生长发育、生产性能以及生理指标的测定。乌金猪的体温为(39.03±0.34)℃,呼吸频率为(28.30±2.31)次/min,脉搏频率为(82.87±3.65)次/min;15min、30min、45min、60min、2h、24h的血沉值分别为(2.67±0.88)mm、(5.33±1.54)mm、(9.87±2.33)mm、(15.07±3.34)mm、(29.43±4.07)mm、(98.10±9.98)mm;血红蛋白含量为(158.00±21.00)g/L,红细胞含量为(6.00±0.39)×1012个/L,白细胞含量为(12.36±1.18)×109个/L,嗜酸性白细胞含量为(2.40±0.39)×108个/L,血小板数为(23.03±3.12)×1010个/L。白细胞分类计数:嗜酸性白细胞占(3.14±0.86)%,嗜碱性白细胞占(0.60±0.77)%,嗜中性晚幼白细胞占(0.00±0.00)%,嗜中性杆状核白细胞占(3.03±0.62)%,嗜中性分叶核白细胞占(33.90±3.25)%,淋巴细胞占(55.83±3.42)%,单核细胞占(3.50±0.63)%。     

Genetic structure of pig breeds from Korea and China using microsatellite loci analysis

To understand molecular genetic characteristics of Korean pigs, the genetic relationships of nine pig breeds including two Korean pigs (Korean native pig and Korean wild pig), three Chinese pigs (Min pig, Xiang pig, and Wuzhishan pig), and four European breeds (Berkshire, Duroc, Landrace, and Yorkshire) were characterized from a 16-microsatellite loci analysis. The mean heterozygosity within breeds ranged from 0.494 to 0.703. Across multiple loci, significant deviation from Hardy-Weinberg equilibrium was observed in most pig breeds, except for two Chinese pigs (Min pig and Wuzhishan pig). This deviation was in the direction of heterozygote deficit. Across population loci, 36 of 144 significantly deviated (P < 0.05) from Hardy-Weinberg equilibrium. The mean FST, a measure of genetic divergence among subpopulations, of all loci indicated that 26.1% of total variation could be attributed to the breed difference. Relationship trees based on the Nei's DA genetic distance and scatter diagram from principal component analysis consistently displayed pronounced genetic differentiation among the Korean wild pig, Xiang pig, and Wuzhishan pig. Individual assignment test using a Bayesian method showed 100% success in assigning Korean and Chinese individual pigs into their correct breeds of origin and 100% exclusion success from all alternative reference populations at P < 0.001. These findings indicate that the Korean native pig has been experiencing progressive interbreeding with Western pig breeds after originating from a North China pig breed with a black coat color. Considering the close genetic relationship of Korean pigs to the Western breeds such as Berkshire and Landrace, our findings can be used as valuable genetic information for the preservation and further genetic improvement of the Korean native pig.     

Identification and quantification of subsidies relevant to the production of local and imported pig breeds in Vietnam

Livestock diversity contributes in many ways to human survival and well-being, while its loss reduces options for attaining sustainable agriculture and universal food security. The current rapid rate of loss of this diversity is the result of a number of underlying factors. While in some cases changes in production systems and consumer preferences reflect the natural evolution of developing economies and markets, in other cases production systems, breed choice and consumer preferences have been distorted by local, national and international policy. In the context of a widespread threat to local pig breeds in Vietnam, this paper identifies and quantifies the level of agricultural subsidies that are currently contributing to this process of breed substitution. Producer subsidies—which tend to improve the competitiveness of imported breeds and their crosses over local breeds—are shown to be considerable, and mitigating measures are now urgently needed to avoid an irreversible loss of livestock diversity.     

Diversity analysis of sheep breeds from Southern peninsular and Eastern regions of India

Information is presented on the genetic diversity and relationship among six Indian sheep breeds/populations belonging to the Southern peninsular and Eastern agroecological zones, based on microsatellite markers. Parameters of genetic variation, viz., allele diversity, observed heterozygosity, gene diversity and population inbreeding estimates, were calculated for the six breeds. The allele diversity ranged from 6.40 to 7.92, whereas the gene diversity varied from 0.617 to 0.727. The highest allele and gene diversity was observed for Nellore sheep, while the lowest was exhibited by Garole breed. Within population inbreeding estimate (F _IS) revealed a significant deficit of heterozygotes in Deccani, Madgyal, Nellore and Garole, whereas Ganjam and Chhotanagpuri sheep showed an excess of heterozygotes. The contribution of each breed to the total diversity of the breeds was quantified by the Weitzman approach. The marginal loss of diversity incurred with removal of Nellore and Garole breeds was higher (>27%), whereas removal of Deccani breed resulted in lowest loss of diversity (3.84%) from the set. Estimation of the genetic differentiation (F _ST) and genetic distance (D _A) between the pairs of breeds revealed a close relationship between Deccani and Madgyal sheep (F _ST = 0.017; D _A = 0.080) and greatest demarcation between Madgyal and Garole breeds (F _ST = 0.110; D _A = 0.622). The information generated would help in shaping genetic management and conservation programs for the sheep breeds under consideration.     

Opportunities for conservation and utilisation of local pig breeds in low-input production systems in Zimbabwe and South Africa

Purpose and methods

In situ conservation of pig genetic resources requires understanding of the farming systems under which the pigs are kept. The objective of the study was to characterise smallholder pig production systems where indigenous pigs are kept in order to assess opportunities for in situ conservation of these pigs. Factors influencing pig herd sizes, ranking of pigs in smallholder production systems, breeds and breed preferences, pig ownership patterns, traits preferred by farmers and constraints to production were investigated in a survey involving 199 farmers from Chirimhanzu District of Zimbabwe, Vhembe, Alfred Nzo and O. R. Tambo Districts of South Africa.

Results

Income was the major factor influencing most pig production related parameters. Most pigs (69.67 %) were owned by women, with most of the women falling into the very low income group. Farmers kept pigs for several reasons that were common across geographical zones and income groups. The odds of a farmer ranking pigs first in the production system depended on the absence of other livestock (P?<?0.05). Farmers in the higher income group tended to mention poor feed resources and access to information as constraints (P?<?0.05) compared to the very low income group. There was preference heterogeneity in the breeds kept and the reasons for breed choice across the income groups and geographical zones. Fewer farmers in the very low income group (42.62 %) recognised the need to conserve local pigs compared to the low income group (80.49 %), the medium income group (50.00 %) and the high income group (100.00 %; χ ²?=?19.14; P?<?0.001).

Conclusions

It was concluded that farmers see value in local pigs and are willing to conserve them. In situ conservation programmes are possible and these should recognise the role of poor women in conserving and enhancing indigenous pig genetic resources.     

荣昌猪和两种小型猪遗传背景的微卫星分析

荣昌猪是我国优良地方品种,巴马香猪和贵州小型香猪为我国独特小型猪品系。本研究采用美国猪基因组协作计划推荐的19个微卫星标记对荣昌猪、荣昌猪B系、巴马香猪、贵州小型香猪及外来猪种大白猪进行了遗传学检测和分析。结果表明:19个微卫星位点在群体中均表现为多态,每位点等位基因数10~23个。5个猪种中荣昌猪B系的遗传多样性最高,荣昌猪次之;2种小型猪的遗传多样性较低,其中巴马香猪的等位基因数(121个)略大于贵州小型香猪(114个),但其遗传多样性指数(平均期望杂合度0.6535±0.0347)小于贵州小型香猪(0.6919±0.0227),反映了巴马香猪较低的基因杂合度和较小的遗传变异;大白猪的遗传多样性最低。从品系的共有等位基因来看,荣昌猪B系基因背景组成中其亲本品系荣昌猪所占比例(30.22%)要大于大白猪(24.37%);大白猪和其他4个猪群体的共享等位基因数均较低(21.24%~25.12%);巴马香猪和贵州小型香猪之间共有等位基因数最高(45.06%)。采用基于遗传距离的NJ法和基于基因频率的最大似然法进行系统聚类,除了大白猪明显为独立分支及荣昌猪B系表现出较远的聚类关系外,其他3个猪种间的聚类有所不同。     

国外猪种大量引进导致本土猪种濒临灭绝的原因分析及应对建议(以玉山黑猪为例)

玉山黑猪,距今已有两千多年的饲养历史,像国内其他地方猪种一样,都是老祖宗留给后人的宝贵财富.20世纪80年代以前,农村家庭养猪以饲养地方猪种为主,以玉山黑猪为例,1981年调查时有生产公猪52头,生产母猪9700头,但自从20世纪80年代后期我国大量引进外国瘦肉型猪后,为追求高产肉量和短期经济效益,养猪户纷纷转向养殖外...     

Comparison of Vietnamese and European pig breeds using microsatellites

This study characterized autochthonous pig breeds of Vietnam and compared them with breeds from other regions. A total of 343 animals were considered from 5 indigenous pig breeds of Vietnam (Muong Khuong, Co, Meo, Tap Na, and Mong Cai), 2 exotic breeds kept in Vietnam (Landrace and Yorkshire), 3 European commercial breeds (German Land-race, Piétrain, and Large White), the Chinese breed Meishan, and the European Wild Boar. Each individual was genotyped for 20 selected polymorphic microsatellite loci. The Vietnamese autochthonous breeds showed higher degrees of polymorphism, allelic diversity, and heterozygosity than the other pig breeds. Also, large genetic diversity was observed across the area of distribution, with village-specific subpopulations, which led to significant inbreeding coefficients. As expected, genetic distances showed large differences among European-based, Chinese, and Vietnamese indigenous breeds and reflected the geographical distribution of breeds. In comparison with the European breeds, the Vietnamese indigenous pig breeds harbored a considerable amount of genetic diversity and, therefore, will be of significance for livestock bioconservation.     

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.     

利用微卫星标记对地方鸡种群体遗传结构的聚类分析

利用29个微卫星标记,通过计算亚群体杂合度（Hs）、总群体杂合度（Ht）、遗传分化系数（Gst）和基因流（Nm）,并基于Reynolds遗传距离、Nei遗传距离运用NJ和UPGMA聚类法构建4类聚类图,比较分析国家地方禽种遗传资源基因库保存的7个地方鸡品种（仙居鸡、鹿苑鸡、固始鸡、大骨鸡、河南斗鸡、狼山鸡、萧山鸡）间的遗传分化和亲缘关系。结果表明,7个地方鸡种29个微卫星座位的总群体杂合度、亚群体杂合度的平均值为0.642,0.551;平均遗传分化系数为0.142。7个地方鸡品种间,萧山鸡与鹿苑鸡的基因流动最大,为5.832 7;狼山鸡与固始鸡的基因流动最小,为0.805 3;基于Reyonalds遗传距离运用NJ聚类法获得的7个鸡种间的亲缘关系聚类图较为准确地反映了7个地方鸡种间的遗传分化和亲缘关系。