畜禽羽色候选基因ASIP和TYRP1的研究进展

羽色是畜禽重要的品种特征之一,是一种易观察的表型性状。畜禽的羽色性状由许多基因控制,其中目前研究较多的主要有黑素皮质素受体1(MC1R)、刺鼠信号蛋白基因(ASIP)、黑素亲和素(MLPH)、溶质载体家族(SLC24A5、SLC45A2)、酪氨酸酶(TYR)家族(TYR、TYRP1、TYRP2)等,各基因间相互作用形成了不同的羽毛颜色。本文简要介绍黑色素的形成机理及研究概况,并对畜禽羽色相关基因ASIP和TYRP1的遗传机制及研究进展进行综述,以便为进一步研究畜禽羽色形成的分子遗传机制提供参考。     

SLC45A2基因在“豫粉1号”浅芦花羽色中的表达及酪氨酸对其在黑色素细胞中表达量的影响

SLC45A2是羽色遗传的重要候选基因,本实验以"豫粉1号"H系为研究对象,其颈部背侧具有黑白相间的芦花色羽毛,颈部腹侧为白色羽毛,利用qRT-PCR技术测定SLC45A2在颈部不同部位(颈部背侧和颈部腹侧)的相对表达量,并研究了在黑色素细胞中添加不同浓度(0、10-9、10-8、10-7、10-6 mol/L)的酪氨酸对SLC45A2表达量的影响。结果表明:SLC45A2在颈部背侧浅芦花和腹侧白色中的表达量差异显著;黑色素细胞添加不同浓度的酪氨酸可以显著影响SLC45A2的表达量,生物信息学分析表明,该基因编码蛋白为跨膜蛋白、不可溶性蛋白。由此表明,SLC45A2可以通过调控黑色素细胞的合成,进而影响"豫粉1号"H系浅芦花羽色的形成。     

MC1R基因在狄高肉鸡配套系羽色纯化中的应用

研究以MC1R基因为鸡羽色性状候选基因,以狄高肉鸡配套系为研究对象,采用序列测定和遗传标记等技术,分析了狄高肉鸡配套系羽色与MC1R基因之间的关系。结果表明,在狄高肉鸡MC1R基因编码区共检测到8个SNP位点,构建了3个单倍型。单倍型1为有色羽AB系与C系主要单倍型,单倍型2为隐性白羽D系主要单倍型,单倍型3是AB系变异单倍型。建立的MC1R基因HaeⅡPCR-RFLP遗传标记,可用于狄高肉鸡SNP5基因分型与单倍型3的检测。研究结果对了解狄高肉鸡配套系羽色传递规律以及羽色纯化具有重要意义。     

新疆天山马鹿血液蛋白多态的研究

采用垂直板聚丙烯酰胺凝胶电泳技术,分析了40头新疆天山马鹿的血清白蛋白(Alb),前白蛋白(Pro),转铁蛋白(Tf),前转铁蛋白(Prt),血红蛋白(Hb)5个蛋白座位的基因型频率、基因频率和群体遗传变异指标,以便为天山马鹿选种选配繁育工作提供理论依据。结果表明,Alb座位呈单态为AA型,其余各蛋白座位均呈多态。Pro有1种基因型AB,受A、B 2个等位基因控制;Hb有2种基因型AB、BB,受A、B 2个等位基因所控制;Prt有5种基因型AA、AB、BB、AC、BC,受A、B、C 3个等位基因控制;Tf有4种基因型AB、BB、AC、BC,受A、B、C 3个等位基因控制。群体遗传变异分析结果表明,Prt、Tf、Alb、Pro、Hb的杂合度分别为0.667,0.610,0,0.513,0.431。基因多态信息含量分别为0.575,0.528,0,0.375,0.332。平均杂合度为0.4442,平均多态信息含量为0.362,表明天山马鹿的遗传多样性丰富,具有较大的遗传潜力。     

利用双侧翼标记进行QTL定位的回归分析法

利用双侧翼标记进行 QTL定位的回归分析法最初是由 Haley和 Knott( 1992 )提出的 ,以下将该方法作一介绍。1　基本假定假定有二个近交群体 ,一个群体具有AQB/AQB基因型 ,另一个具有 aqb/aqb基因型 ,其中 A和 B是遗传标记座位 ,都有二个等位基因 ,分别用大小写字母表示 ,Q是数量性状基因座位 ,同样有二个等位基因 ( Q和q) ,且位于二个标记座位中间。二个群体杂交产生 F1代 ,F1代自交产生 F2 代 ,在 F2 代中分离出三种数量性状的基因型 ,QQ,Qq和qq,期望平均数分别用 ( m+ a) ,( m+ d)和 ( m- a)表示 ,m是中亲值 (二纯合子平均数 ) ,a…     

他留乌骨鸡SLC24A5基因Nhe I mismatch PCR-RFLP标记与羽色及肤色相关性研究

采用PCR测序与PCR-RFLP技术,研究了SLC24A5基因变异与他留乌骨鸡羽色及肤色的关系。通过对他留乌骨鸡麻羽、白羽和黑羽3个品系以及乌骨与非乌骨2个类型的SLC24A5基因个体测序,共检测到19个SNP位点,其中3个位点引起氨基酸变异。采用每个品系或类型PCR扩增池测序技术,确定了每个SNP位点在不同品系或类型的基因频率,在分析基因频率差异及SNP变异特性的基础上,针对G482C位点,建立了Nhe I mismatch PCR-RFLP分子标记。利用该遗传标记对所有受试个体进行基因分型,并分析其与羽色肤色性状的相关性。结果表明,SLC24A5基因Nhe I mismatch PCR-RFLP分子标记与肤色性状显著相关。     

云南保种山羊血液同工酶遗传多样性研究

采用水平式淀粉胶电泳技术 ,对云南龙陵黄山羊、宁蒗黑头山羊、马关无角山羊和路南圭山羊等 4个保种山羊的 1 2 0个个体共 3 9个基因座位的基因多态性进行了研究。结果显示 ,云南 4个保种山羊品种在AKP、CES - 1、ESD、GOI、LAP、MDH、ME和NP基因座位出现多态。多态座位基因在不同保种山羊中分布不同。多态基因座位百分比 (P)在 4个保种山羊中分别为 0 .2 0 51 ,0 .1 53 8,0 .1 2 82和 0 .1 53 8。平均杂合度 (H)分别为 0 .0 95,0 .0 61 4 ,0 .0 4 67和 0 .0 662。用UPGMA法对由基因频率计算得到的Nei氏标准遗传距离进行聚类分析 ,结果表明云南保种山羊具地理分布及品种特点 ,龙陵黄山羊和其它 3个品种的遗传距离最远。     

3个纯系商品肉鸡MHC微卫星标记的遗传多样性研究

分析了3个纯系商品肉鸡MHC和非-MHC位点的遗传多态性。用Southern杂交技术检测MHC-Ⅰ型和Ⅳ型位点，并判定RFLP的基因型。在这些肉鸡品系中，检测到4种MHC一Ⅱ型和8种Ⅳ型基因型，它们的基因频率不同。检测了各个品系的特异性MHC基因型。杂合度(59％～67％)显示这些品系的MHC位点具有高度的多态性，MHC位点至少9％的遗传变异是由品系差异引起的。为了检测非-MHC基因，对这3个品系肉鸡非MHC基因组上41微卫生位点进行研究，结果发现它们的微卫星位点存在遗传变异；每个位点等位基因数范围为1～8个。每个品系的平均等位基因数分别为3．5、2．8、3．1。座位的杂合度范围为0％～89％。通过对固定指数(Fst)的分析，发现该基因微卫星座位的遗传差异19％是品系间差异造成的。对MHC和非-MHC座位进行Hardr-Weinberg平衡定律检验，结果2个位点处于连锁不平衡。这可能是由遗传选择或非等位基因存在造成的。本研究主要阐明了商品代肉鸡的群体分子遗传特性和遗传结构。MHC和非-MHC位点的研究结果表明：肉种品系仍具有丰富的遗传多样性，可为继续提高肉鸡的生产性能提供有用的基因资源。     

基于RAD-seq静原鸡保种群体的遗传变异分析

旨在分析静原鸡白羽、麻羽、黑羽保种群之间的遗传变异,挖掘调控特征性状的关键候选基因。本研究利用RAD-seq技术对180日龄特征明显、发育正常且健康的白羽、麻羽、黑羽静原鸡(每个羽色选取60个个体,40只母鸡,20只公鸡)进行测序,基于SNP标记计算观察杂合度(Ho)、群体内核酸多态性(Pi)、群体的平均近交系数(Fis)等指标,分析静原鸡3个类群的遗传多样性和群体结构,并通过选择性清除分析和全基因组关联分析(GWAS)筛选出候选基因,利用KOBAS对候选基因进行KEGG (Kyoto Encyclopedia of Genes and Genomes)通路富集,最终筛选出调控静原鸡羽色的候选基因。测序结果表明,静原鸡180个样品共产生198.83 Gb Clean Data,Q30达到93%以上。遗传多样性分析表明,白羽、麻羽、黑羽静原鸡分别鉴定出238 533、233 562和240 820个SNPs标记,Ho、Pi和Fis分别在0.273 2~0.278 2、0.304 9~0.309 6和0.096 1~0.109 8之间。群体结构分析表明,静原鸡根据不同羽色分为不同类群。通过选择性清除分析和全基因组关联分析共筛选出11个(FZD4、WNT16、EDNRB、TYR、KRAS、CTNNB1、DDC、MC1R、CAMK2A、PRKCB、PRKCA)与静原鸡羽色相关的候选基因,富集结果显示这些基因主要与黑色素生成、酪氨酸代谢和Wnt信号传导等通路相关。综上所述,本研究利用SNPs标记信息可以全面地评价静原鸡的保种现状,为静原鸡的遗传资源保护奠定理论基础。同时,筛选出了与静原鸡羽色性状相关的候选基因,为静原鸡不同羽色的品系化培育提供新的遗传标记和基因靶点。     

他留乌骨鸡TYR基因多态性与色素性状相关性分析

通过研究鸡酪氨酸酶(TYR)基因多态性与羽色、肤色等色素性状相关性,为他留乌骨鸡色素性状基因纯化及分子标记选择提供科学依据。采用PCR扩增池测序与PCR-RFLP标记技术,研究他留乌骨鸡麻羽、白羽和黑羽3个羽色类群以及乌骨鸡与非乌骨鸡2种类群的TYR基因多态性,计算等位基因频率与基因型频率,并与色素性状进行了关联分析。结果显示,在他留乌骨鸡中共检测到20个SNP位点,其中2个SNP引起氨基酸改变。建立了TYR基因HindⅢ和MseⅠ两个PCR-RFLP分子标记,利用这两个标记对所有受试个体进行基因分型,关联分析提示,他留乌骨鸡TYR基因变异与羽色性状显著相关,但与肤色等乌骨性状相关不显著。TYR基因MseⅠPCR-RFLP标记可能是影响羽色性状变异的一个分子标记。     

A gene co‐expression network analysis of the candidate genes and molecular pathways associated with feather follicle traits of chicken skin

Back and thigh skin of chickens showed significant differences in the thickness and the feather follicle density and size, which are important traits for slaughtered chickens' appearance. In the present study, global gene expression profiling was conducted in the back and thigh skin of chickens using Microarray technology. The results showed that 676 genes were differentially expressed between back and thigh skin. The expression of the differentially expressed genes (DEGs), including PPP1R3C, IGF1, PTCHD1, HOXB6, FGF9, CAMK4, SHH, BMP8B, FOXN1 and PTGER2, was validated by real‐time quantitative polymerase chain reaction (RT‐qPCR), and the results were consistent with microarray results. Functional analysis revealed that the DEGs were significantly involved in cell proliferation, differentiation, apoptosis, adhesion and transport process, and the pathways were significantly mapped into the ECM‐receptor interaction, peroxisome, focal adhesion, Hedgehog and PPAR signalling pathways. Protein–protein interaction network analysis suggested that signalling pathways related to feathers morphogenesis and development, such as Wnt, FGF, MAPK, SHH and BMP signalling pathways, occupied important positions in the network. Genes involved in these signalling pathways and adhesion molecules might play a vital role in skin and feather follicle development. Further single nucleotide polymorphism (SNP) association analysis of Wnt3A showed that the AC genotype of SNP g.255361 C>A significantly increased the feather follicle density of thigh skin. Our findings may provide new insights on candidate genes and pathways related to skin and feather follicle formation of chickens.     

Molecular characteristics of MC1R gene in tile-grey plumage of domestic chicken

ABSTRACT

1. Tile-grey plumage is a unique and rare feather type of local chicken breeds in China, but its genetic mechanism and corresponding genes remain unknown.

2. In order to identify the genetic basis and molecular characteristics of tile-grey plumage, this experiment investigated variations of melanocortin 1 receptor (MC1R) gene in Yunnan Piao chickens with typical tile-grey plumage characteristics in contrast with three Yunnan local breeds as well as two standard breeds with different plumage colour, and analysed the association between genic variation and tile-grey plumage.

3. Through sequencing and comparison of the entire coding region of the MC1R gene, a total of 10 SNP loci were detected, of which eight were non-synonymous mutations that cause amino acid changes. The gene frequency and genotype frequency of the MC1R mutation sites in different breeds and different plumage colour groups revealed that C69T, T212C and A274G were significantly associated with tile-grey plumage. Eighteen haplotypes of the MC1R gene were constructed based on 10 nucleotide variations and eight amino acid variations. Haplotype distribution and the median joining network in breeds and plumage colour groups revealed a main haplotype (hap2) for tile-grey plumage. Hap2 is unique to the tile-grey feather of Piao chicken, and the individuals carrying this haplotype account for 62.96% of the whole tile-grey chicken.

4. The results of this study are of significance for further analysis of the molecular basis of tile-grey plumage and the selective breeding of tile-grey plumage.     

Polymorphism Analysis of the Agouti-related Protein Gene Exon Ⅰof Quail

The poultry feather color inheritance has been a hot research topic, because the feather color is a kind of important quality character.In this study, we used polyacrylamide gel electrophoresis to detect the polymorphisms of four quail populations of different feather color (China Yellow quail, Black quail, Korean quail, Beijing White quail) of agouti-related protein gene (Agrp) exon Ⅰ, so as to investigate the relationship of Agrp exon I with quail plumage color, and to provide reference for the breeding and production of quail.The results showed that two alleles were detected in the Agrp exon Ⅰ of China Yellow quail, Black quail, Korean quail, Beijing White quail populations,and expressed by A and B, respectively. Frequency of allele A in Beijing White quail was up to 0.9500. The frequency of B allele in Korean quail was the highest, reaching 0.3392, in Beijing White quail genes in the lowest frequency is only 0.0500. The genotype frequency of AA genotype in Beijing White quail was the highest (0.9500), the lowest in Korean quail and Black quail (0.4286). BB genotype was not observed in Beijing White quail. We speculated that it may have a certain relationship between Agrp exon Ⅰ B allele and feather color of quail.     

鹌鹑野灰相关蛋白基因外显子Ⅰ的多态性分析

家禽的羽色遗传一直是炙手可热的研究课题,因为羽色是禽类一种重要的质量性状。本研究利用聚丙烯凝胶电泳技术对不同羽色的4个鹌鹑群体（中国黄羽鹌鹑、黑羽鹌鹑、朝鲜鹌鹑、北京白羽鹌鹑）进行野灰相关蛋白基因（agouti-related protein,Agrp）外显子Ⅰ的多态性检测,探讨Agrp外显子Ⅰ与鹌鹑羽毛颜色的关系,为鹌鹑的育种及生产提供参考。结果表明,Agrp外显子Ⅰ在中国黄羽鹌鹑、黑羽鹌鹑、朝鲜鹌鹑、北京白羽鹌鹑群体中都检测到了2个等位基因,分别用A和B表示。等位基因A在北京白羽鹌鹑中的基因频率最高,达到了0.9500。B等位基因在朝鲜鹌鹑中的频率最高,达到了0.3392,在北京白羽鹌鹑中的基因频率最低,只有0.0500。基因型AA在北京白羽鹌鹑中的基因型频率最高（0.9500）,在朝鲜鹌鹑和黑羽鹌鹑中最低（0.4286）。基因型AB在北京白羽鹌鹑中没有出现。测序发现,在黑羽鹌鹑和朝鲜鹌鹑中有AG的杂合位点,而在北京白羽鹌鹑中只有G位点。推测Agrp外显子Ⅰ的AB基因型（或B等位基因）与鹌鹑的黑羽色可能有一定关系。     

朝鲜鹌鹑黑素皮质素受体1基因多态性及其在不同羽色个体中的表达

通过混合样品DNA测序方法寻找黑素皮质素受体l（MC1R）基因的突变位点,采用Alu1-RFLP对突变位点在4种羽色（栗羽、黄羽、白羽、黑羽）鹌鹑群体中的基因分布进行了研究;利用qRT-PCR技术测定了MC1R基因在12日龄时4种羽色鹌鹑胚胎皮肤组织中的表达情况。结果表明,在鹌鹑MC1R基因上发现1个T/C突变位点,该位点没有导致编码蛋白氨基酸序列改变,A1u1-RFLP分析发现,该突变位点的不同基因型在4种羽色鹌鹑群体间的分布有显著差异（P〈0.05）。4种羽色鹌鹑皮肤组织中MC1R基因的表达量存在明显差异,栗羽鹌鹑皮肤组织中该基因的表达量明显高于黑羽鹌鹑皮肤中的表达量（栗羽〉黄羽〉白羽〉黑羽）。本试验没有发现导致日本鹌鹑黑羽突变的Glu92Lys突变位点,表明朝鲜鹌鹑的黑羽突变与报道的日本鹌鹑黑羽突变的机制不同,朝鲜鹌鹑的黑羽可能与其他基因的突变有关。     

培育品系中鸡青胫性状的遗传规律分析及分子基础初探

深受中国消费者青睐的青胫性状受隐性伴性基因或常染色体显性基因控制。为探明培育品系W系青胫性状的遗传规律及分子基础,本研究首先选取W系黑羽青胫与洛岛红黄羽黄胫的成熟公、母鸡(1♂∶5♀)进行正反交试验,然后对后代中青、黄胫母雏各4只的胫部皮肤进行转录组测序分析。结果表明,正交后代有青胫293只(♂172只,♀121只),黄胫51只(♂20只,♀31只); 反交后代有青胫256只(♂156只,♀100只),黄胫73只(♂29只,♀44只),正或反交后代均有两种胫色,且青胫显著多于黄胫,表明W系青胫性状属于常染色体显性遗传。将有胫色分离的杂交组合后代按胫色、羽色统计,青、黄胫个体分别为黑、黄羽,青、黄胫分离比符合1∶1(121∶117),因此青、黄胫性状或黑、黄羽性状可能受1对等位基因控制。雏鸡的胫部皮肤转录组测序分析表明,差异表达基因显著富集于黑色素生成通路(P < 0.01),Mc1r基因和已知参与黑色素合成的基因如Tyr、Tyrp1在青、黄胫皮肤中的表达量存在极显著差异。另外,一些尚无报道参与胫色形成的基因如Wnt16、Wnt3a、Fzd10等也存在极显著差异。青胫性状的形成除涉及显著富集的黑色素生成通路外,还涉及细胞外基质与受体信号、信号传导、细胞骨架与迁移、细胞黏附、鞘脂与糖脂代谢。综合遗传分析与转录组分析,本研究推定培育品系W系中的青胫性状受Mc1r基因控制,呈常染色体显性遗传,青胫性状的形成涉及多个信号通路,这为青胫性状形成机制的阐明奠定了基础。     

北京油鸡快慢羽公鸡鉴定及羽毛发育、生长和繁殖性能的对比分析

试验通过开展快慢羽群体的鉴定,并对比其在羽毛发育、生长和繁殖性能方面的差异,旨在为北京油鸡种鸡选育和科学养殖提供数据支持。选用北京油鸡纯系公鸡,出雏时,按照主翼羽与覆主翼羽的羽长差值将其分为快慢羽亚群,其中快羽包括K1（主翼羽长于覆主翼羽>5 mm）和K2（主翼羽长于覆主翼羽2~5 mm）,慢羽包括M1（主翼羽与覆主翼羽等长或主翼羽长于覆主翼羽<2 mm）和M2（主翼羽短于覆主翼羽）和M3（主翼羽未长出）。1~7日龄每隔1 d测量1次主翼羽与覆主翼羽羽长,7~42日龄每隔1周测量1次;1~8周龄每周测量体重,9~18周龄每隔1周测定体重;10周龄时,观测公鸡全身羽毛发育情况;47周龄时,测定公鸡常规精液品质性状、精子动力学参数、受精率及孵化率。结果显示,快羽公鸡占北京油鸡公鸡总数的11.60%,慢羽占88.40%,慢羽又以M2型为主,有少量M1型和M3型。育雏育成期（1~18周）北京油鸡快慢羽公鸡各周龄体重均无显著差异（P>0.05）。在育雏育成期,慢羽公鸡主翼羽和覆主翼羽生长均慢于快羽公鸡。其10周龄时,背部和腿部羽毛生长完全的鸡的比例仅为44%,且不同类型的慢羽公鸡的比例也不一,其中等长型或微长型慢羽最高,超过90%,未长出型慢羽最低,仅为17%左右。47周龄时快羽鸡和慢羽鸡的常规精液品质无差异,但是快羽公鸡精子直线性显著高于慢羽鸡（P<0.05）,直线速率高于慢羽公鸡（P=0.06）,快羽北京油鸡公鸡受精率显著高于慢羽公鸡（P<0.05）,且入孵蛋孵化率和受精蛋孵化率有高于慢羽公鸡的趋势,但差异不显著（P>0.05）。本研究结果表明,快慢羽北京油鸡公鸡的羽毛生长和繁殖性能有一定差异,需要加强慢羽公鸡羽毛发育缓慢原因和鉴定方法的研究,也需加强慢羽公鸡精液品质选育。     

Plumage colour and feather pecking in laying hens,a chicken perspective?

1. This study investigated whether feather damage due to feather pecking and bird behaviour were influenced by plumage colour in Oakham Blue laying hens (black, white, grey colour variants). The reflectance properties of feathers and spectral composition of light environments experienced by the hens were also examined. 2. Nine hundred and seventy-nine birds were inspected and scored for feather damage; 10.5 h of video recordings were examined to record feather pecking and bird behaviour. Feathers and light environments were measured using a USB-2000 spectrometer and DH-2000-CAL-DTH lamp. 3. Oakham Blue birds with white plumage had less feather damage due to feather pecking than black or grey birds. There was more severe feather pecking in the mornings than in the afternoon. White birds feather pecked severely more than black or grey birds, although there were no other behavioural differences between plumage colours. 4. White feathers reflected at a higher intensity than black or grey feathers. However, black and grey feather spectra were relatively flat and the contribution of UV wavelengths to plumage reflection was proportionally greater than that for white feathers. 5. Light intensity inside a poultry house was 100 x (UW/cm2/nm) less than on the range and there was low or no UV reflectance. Under the dim, artificial lights inside a poultry house, Oakham Blue hens with black and grey feathers may be less visible to conspecifics than white birds because their plumage reflects at a lower intensity. Furthermore, the lack of available UV light inside vs. outside and the higher contribution of UV reflectance to black and grey plumage may make black and grey birds appear more different inside the house than white birds. It is possible that this novel/unusual appearance may make black or grey Oakham Blue hens more susceptible to feather pecking.