Der Sarkissian Clio, Ermini Luca, Schubert Mikkel, Yang Melinda A, Librado Pablo, Fumagalli Matteo, Jónsson Hákon, Bar-Gal Gila Kahila, Albrechtsen Anders, Vieira Filipe G, Petersen Bent, Ginolhac Aurélien, Seguin-Orlando Andaine, Magnussen Kim, Fages Antoine, Gamba Cristina, Lorente-Galdos Belen, Polani Sagi, Steiner Cynthia, Neuditschko Markus, Jagannathan Vidhya, Feh Claudia, Greenblatt Charles L, Ludwig Arne, Abramson Natalia I, Zimmermann Waltraut, Schafberg Renate, Tikhonov Alexei, Sicheritz-Ponten Thomas, Willerslev Eske, Marques-Bonet Tomas, Ryder Oliver A, McCue Molly, Rieder Stefan, Leeb Tosso, Slatkin Montgomery, Orlando Ludovic
Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen 1350K, Denmark.
Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720-3140, USA.
Curr Biol. 2015 Oct 5;25(19):2577-83. doi: 10.1016/j.cub.2015.08.032. Epub 2015 Sep 24.
Przewalski's horses (PHs, Equus ferus ssp. przewalskii) were discovered in the Asian steppes in the 1870s and represent the last remaining true wild horses. PHs became extinct in the wild in the 1960s but survived in captivity, thanks to major conservation efforts. The current population is still endangered, with just 2,109 individuals, one-quarter of which are in Chinese and Mongolian reintroduction reserves [1]. These horses descend from a founding population of 12 wild-caught PHs and possibly up to four domesticated individuals [2-4]. With a stocky build, an erect mane, and stripped and short legs, they are phenotypically and behaviorally distinct from domesticated horses (DHs, Equus caballus). Here, we sequenced the complete genomes of 11 PHs, representing all founding lineages, and five historical specimens dated to 1878-1929 CE, including the Holotype. These were compared to the hitherto-most-extensive genome dataset characterized for horses, comprising 21 new genomes. We found that loci showing the most genetic differentiation with DHs were enriched in genes involved in metabolism, cardiac disorders, muscle contraction, reproduction, behavior, and signaling pathways. We also show that DH and PH populations split ∼45,000 years ago and have remained connected by gene-flow thereafter. Finally, we monitor the genomic impact of ∼110 years of captivity, revealing reduced heterozygosity, increased inbreeding, and variable introgression of domestic alleles, ranging from non-detectable to as much as 31.1%. This, together with the identification of ancestry informative markers and corrections to the International Studbook, establishes a framework for evaluating the persistence of genetic variation in future reintroduced populations.
普氏野马（PHs，学名：Equus ferus ssp. przewalskii）于19世纪70年代在亚洲草原被发现，是现存最后一种真正的野马。普氏野马在20世纪60年代野外灭绝，但由于大量的保护工作，在圈养环境中得以存活。目前其种群仍处于濒危状态，仅有2109匹，其中四分之一在中国和蒙古的重新引入保护区[1]。这些马起源于12匹野生捕获的普氏野马，可能还包括多达4匹驯化个体[2-4]。它们体型矮壮，鬃毛直立，腿部短且有条纹，在表型和行为上与家马（DHs，学名：Equus caballus）不同。在此，我们对11匹普氏野马的完整基因组进行了测序，这些个体代表了所有的奠基谱系，还对5个可追溯到公元1878 - 1929年的历史标本进行了测序，包括模式标本。我们将这些序列与迄今为止最广泛的马基因组数据集进行了比较，该数据集包含21个新基因组。我们发现，与家马相比，显示出最大遗传分化的基因座在参与代谢、心脏疾病、肌肉收缩、繁殖、行为和信号通路的基因中富集。我们还表明，家马和普氏野马种群在约45000年前分化，此后通过基因流保持联系。最后，我们监测了约110年圈养对基因组的影响，发现杂合性降低、近亲繁殖增加以及家马等位基因的可变渗入，渗入率从不可检测到高达31.1%。这与祖先信息标记的识别以及对国际谱系登记册的修正一起，建立了一个评估未来重新引入种群中遗传变异持久性的框架。
