Data from: P53 gene discriminates two ecologically divergent sister species of pine voles

Genes with relevant roles in the differentiation of closely-related species are likely to have diverged simultaneously with the species and more accurately reproduce the species tree. The Lusitanian (Microtus lusitanicus) and Mediterranean (M. duodecimcostatus) pine voles are two recently separated sister species with fossorial lifestyles whose different ecological, physiological and morphological phenotypes reflect the better adaptation of M. duodecimcostatus to the underground habitat. Here we asked whether the differentiation of M. lusitanicus and M. duodecimcostatus involved genetic variations within the tumour suppressor p53 gene, given its role in stress-associated responses. We performed a population-genetic analysis through sequencing of exons and introns of p53 in individuals from sympatric and allopatric populations of both the species in the Iberian Peninsula in which a unidirectional introgression of mitochondrial DNA was previously observed. We were able to discriminate the two species to a large extent. We show that M. duodecimcostatus is composed of one genetically unstructured group of populations sharing a P53 protein that carries a mutation in the DNA-binding region not observed in M. lusitanicus, raising the possibility that this mutation may have been central in the evolutionary history of M. duodecimcostatus. Our results provide suggestive evidence for the involvement of a master transcription factor in the separation of M. lusitanicus and M. duodecimcostatus during Microtus radiation in the Quaternary presumably via a differential adaptive role of the novel p53 in M. duodecimcostatus.

在近缘物种分化中发挥相关作用的基因，大概率会与物种同步发生分化，且能更精准地复现物种树。葡萄牙松田鼠（Microtus lusitanicus）与地中海松田鼠（M. duodecimcostatus）是一对新近分化的姐妹物种，二者均为穴居生活，其生态、生理与形态表型的差异，反映出地中海松田鼠更适应地下生境。鉴于肿瘤抑制基因p53（tumour suppressor p53）在应激相关反应中的核心作用，本研究旨在探究葡萄牙松田鼠与地中海松田鼠的分化过程是否伴随该基因内的遗传变异。我们针对伊比利亚半岛的两种田鼠的同域与异域种群个体，对p53的外显子与内含子进行测序，开展群体遗传学分析——此前该区域曾被观测到存在线粒体DNA的单向基因渐渗现象。我们得以在较大程度上区分这两个物种。研究结果显示，地中海松田鼠由一个遗传结构无分化的种群群组成，其共享的P53蛋白在DNA结合区域存在一处葡萄牙松田鼠未观测到的突变，这提示该突变可能在地中海松田鼠的演化历史中发挥了核心作用。本研究结果提供了初步佐证，表明在第四纪田鼠属辐射演化过程中，这一核心转录因子参与了葡萄牙松田鼠与地中海松田鼠的物种分化，其潜在机制可能是该新型p53在地中海松田鼠中发挥了差异化的适应性功能。