Abstract:
Shades of grey and brown are a dominant component in mammal coat colours, representing a fundamental trait involved in a great number of processes including cryptism, sexual selection and signalling. The genetic mechanisms of the grey colouration in mammals are very complex and controlled by hundreds of genes whose effects and interactions are still largely unclear. In this study, we adopted a robust multi-cohort Fst outlier approach based on pairwise contrasts between seven grey indicine cattle breeds and both taurine and indicine non-grey cattle breeds in order to find genomic regions potentially related to the grey colouration. On the basis of three main drawn settings, built in order to control both the effect of the sample size and the genetic structure, we have identified some signals common to those obtained in a previous work employing only taurine cattle. In particular, using the top 1% Fst approach, we detected a candidate region (22.6-23.8 megabases) on chromosome 14 in which genes related to pigmentation have been already documented. In addition, when we constructed a phylogenetic tree using the significant markers identified in this study and including also the genotyping data at these loci of both the grey taurine and the extinct wild auroch, we found a topological repartition consistent with breed colour pattern rather than with the known bovine evolutionary history. Thus, on the basis of this evidence, together with the geographical distribution of the current taurine grey cattle, an ancestral indicine origin for the grey phenotype would seem to be a conceivable interpretation. In this context, a higher thermo-tolerance and less UV-induced damage of the grey phenotype might have favoured the retention of advantageous genes into the taurine genome during the post-Neolithic human-mediated cattle expansions.
摘要:
灰色和棕色是哺乳动物皮毛颜色的主要组成部分,代表涉及大量过程的基本特征,包括隐秘,性选择和信号。哺乳动物灰色着色的遗传机制非常复杂,并受数百个基因的控制,这些基因的作用和相互作用仍不清楚。在这项研究中,我们采用了一种稳健的多队列Fst异常值方法,该方法基于7个灰色野牛品种与牛磺酸和非灰色野牛品种之间的成对对比,以找到可能与灰色着色相关的基因组区域。在三个主要绘制设置的基础上,为了控制样本量和遗传结构的影响,我们已经确定了一些常见的信号,这些信号在以前的工作中只使用牛磺酸牛。特别是,使用前1%Fst方法,我们在14号染色体上检测到一个候选区域(22.6-23.8兆碱基),其中与色素沉着相关的基因已经被记录.此外,当我们使用本研究中确定的重要标记构建系统发育树时,还包括灰色牛磺酸和已灭绝的野生auroch的这些基因座的基因分型数据,我们发现了与品种颜色模式一致的拓扑重新划分,而不是与已知的牛进化史一致。因此,根据这些证据,加上目前牛磺酸灰牛的地理分布,灰色表型的祖先指标起源似乎是一个可以想象的解释。在这种情况下,在新石器时代人类介导的牛扩增过程中,较高的耐热性和较少的紫外线诱导的灰色表型损害可能有利于将有利基因保留到牛磺酸基因组中。