Batova Olga N, Markov Nikolay I, Titov Sergey V, Tchabovsky Andrey V
Laboratory for Population Ecology, Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, 33 Leninskii Pr., 119071 Moscow, Russia.
Laboratory for Game Animals Ecology, Institute of Plant and Animal Ecology, Ural Branch of Russian Academy of Sciences, 202a 8 Marta St., 620142 Ekaterinburg, Russia.
Animals (Basel). 2024 Sep 20;14(18):2720. doi: 10.3390/ani14182720.
Colonizing populations at the leading edge of range expansion are expected to have a reduced genetic diversity and strong genetic structure caused by genetic drift and allele surfing. Until now, few studies have found the genetic signatures of allele surfing in expanding wild populations. Using mtDNA markers, we studied the genetic structure of the population of midday gerbils () expanding their range to the west in Kalmykia (southern Russia) following the new cycle of desertification, re-colonizing areas abandoned in the mid-2010s. In the colonizing population, we found a reduced genetic diversity, the redistribution of haplotype frequencies-in particular, in favor of variants rare in the core population-and strong genetic structure combined with strong differentiation from the core population-patterns suggestive of allele surfing on the wave of expansion. In terms of genetic diversity and spatial structuration, the western edge population sampled in 2008 before its collapse in 2017 occupies the intermediate position between the current colonizing and core population. This suggests that reduced genetic diversity and increased genetic differentiation are general features of marginal populations, enhanced by the founder and allele-surfing effects at the leading edges of expanding ranges.
在分布范围扩张前沿的定殖种群，预计会因遗传漂变和等位基因冲浪而出现遗传多样性降低和强烈的遗传结构。到目前为止，很少有研究在扩张的野生种群中发现等位基因冲浪的遗传特征。利用线粒体DNA标记，我们研究了子午沙鼠种群的遗传结构，在新一轮沙漠化之后，它们在卡尔梅克（俄罗斯南部）向西扩张其分布范围，重新定殖了2010年代中期被遗弃的地区。在定殖种群中，我们发现遗传多样性降低，单倍型频率重新分布——特别是有利于核心种群中罕见的变异体——以及强烈的遗传结构，同时与核心种群有强烈分化，这些模式表明在扩张浪潮中等位基因冲浪现象。在遗传多样性和空间结构方面，2008年采样的西部边缘种群在2017年崩溃之前，处于当前定殖种群和核心种群之间的中间位置。这表明遗传多样性降低和遗传分化增加是边缘种群的普遍特征，在扩张范围前沿的奠基者效应和等位基因冲浪效应会增强这些特征。
