Whole mitochondrial genome sequencing of domestic horses reveals incorporation of extensive wild horse diversity during domestication

BMC Evolutionary Biology

Research Article

Nicholas J Matzke¹  Monika Reissmann²  Michael Hofreiter³  Sebastian Lippold⁴ 

[1] Center for Theoretical Evolutionary Genomics, Department of Integrative Biology, University of California, Berkeley, 4151 Valley Life Sciences Building, Berkeley, CA, USA;Department for Crop and Animal Sciences, Humboldt University Berlin, Invalidenstr. 42, 10115, Berlin, Germany;Department of Biology, University of York, Wentworth Way, YO10 5DD, Heslington, York, UK;Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103, Leipzig, Germany;

关键词: Complete Mitochondrial Genome;    Global Clock;    Bayesian Skyline Plot;    Horse Breed;    Domestic Horse;   

DOI  :  10.1186/1471-2148-11-328

 received in 2011-07-18, accepted in 2011-11-14,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundDNA target enrichment by micro-array capture combined with high throughput sequencing technologies provides the possibility to obtain large amounts of sequence data (e.g. whole mitochondrial DNA genomes) from multiple individuals at relatively low costs. Previously, whole mitochondrial genome data for domestic horses (Equus caballus) were limited to only a few specimens and only short parts of the mtDNA genome (especially the hypervariable region) were investigated for larger sample sets.ResultsIn this study we investigated whole mitochondrial genomes of 59 domestic horses from 44 breeds and a single Przewalski horse (Equus przewalski) using a recently described multiplex micro-array capture approach. We found 473 variable positions within the domestic horses, 292 of which are parsimony-informative, providing a well resolved phylogenetic tree. Our divergence time estimate suggests that the mitochondrial genomes of modern horse breeds shared a common ancestor around 93,000 years ago and no later than 38,000 years ago. A Bayesian skyline plot (BSP) reveals a significant population expansion beginning 6,000-8,000 years ago with an ongoing exponential growth until the present, similar to other domestic animal species. Our data further suggest that a large sample of wild horse diversity was incorporated into the domestic population; specifically, at least 46 of the mtDNA lineages observed in domestic horses (73%) already existed before the beginning of domestication about 5,000 years ago.ConclusionsOur study provides a window into the maternal origins of extant domestic horses and confirms that modern domestic breeds present a wide sample of the mtDNA diversity found in ancestral, now extinct, wild horse populations. The data obtained allow us to detect a population expansion event coinciding with the beginning of domestication and to estimate both the minimum number of female horses incorporated into the domestic gene pool and the time depth of the domestic horse mtDNA gene pool.

【 授权许可】

CC BY   
© Lippold et al; licensee BioMed Central Ltd. 2011