Álvarez I, Pérez-Pardal L, Traoré A, Koudandé D O, Fernández I, Soudré A, Diarra S, Sanou M, Boussini H, Goyache F
Área de Genética y Reproducción Animal, SERIDA, Camino de Rioseco, Gijón, Spain.
CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, Vairão, Portugal.
J Anim Breed Genet. 2017 Oct;134(5):393-404. doi: 10.1111/jbg.12278. Epub 2017 May 2.
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 -statistics computed between cattle groups tended to be statistically non-significant (p > .05). Most F 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 = 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.
对代表四个牛群的11个不同亚群的多达173头非洲公牛进行了6个Y染色体特异性微卫星位点和一个线粒体DNA片段的分析。评估了Y染色体和线粒体DNA单倍型结构的差异。此外，还评估了这种结构对总遗传多样性贡献的影响。共鉴定出35种Y染色体单倍型和71种线粒体DNA单倍型。分析的大多数Y染色体（73.4%）起源于瘤牛（11种单倍型）。22种Y单倍型（44个样本）属于非洲牛亚科Y2a。所有线粒体DNA单倍型都属于“非洲”牛T1单倍群，其中16个样本和9种单倍型属于最近鉴定出的一个亚单倍群（T1e）。中介网络显示，Y染色体系统发育高度网状，瘤牛和普通牛聚类之间有明显分离。线粒体单倍型呈现出明显的星状，单倍型之间的突变较少。牛群之间基于线粒体的F统计量在统计学上往往不显著（p>0.05）。使用Y染色体标记计算的组间和亚群间的大多数F值在统计学上是显著的。方差分析证实，牛群之间的差异仅在Y染色体标记上显著（Φ=0.209）。在线粒体水平上，非洲公牛类似于一个未分化的群体，个体解释了总方差的94.3%。无论考虑哪种标记，对总奈氏基因多样性和等位基因丰富度贡献最高的是西非牛。遗传结构对多样性贡献模式没有影响。
