Senckenberg Biodiversity and Climate Research Centre, Senckenberganlage 25, 60325 Frankfurt am Main, Germany; Institute for Ecology, Evolution and Diversity, Goethe University, Max-von-Laue-Straße 13, 60438 Frankfurt am Main, Germany.
Senckenberg Biodiversity and Climate Research Centre, Senckenberganlage 25, 60325 Frankfurt am Main, Germany; Institute for Ecology, Evolution and Diversity, Goethe University, Max-von-Laue-Straße 13, 60438 Frankfurt am Main, Germany.
Curr Biol. 2021 Jul 12;31(13):2929-2938.e5. doi: 10.1016/j.cub.2021.04.033. Epub 2021 May 5.
Species is the fundamental taxonomic unit in biology and its delimitation has implications for conservation. In giraffe (Giraffa spp.), multiple taxonomic classifications have been proposed since the early 1900s. However, one species with nine subspecies has been generally accepted, likely due to limited in-depth assessments, subspecies hybridizing in captivity, and anecdotal reports of hybrids in the wild. Giraffe taxonomy received new attention after population genetic studies using traditional genetic markers suggested at least four species. This view has been met with controversy, setting the stage for debate. Genomics is significantly enhancing our understanding of biodiversity and speciation relative to traditional genetic approaches and thus has important implications for species delineation and conservation. We present a high-quality de novo genome assembly of the critically endangered Kordofan giraffe (G. camelopardalis antiquorum) and a comprehensive whole-genome analysis of 50 giraffe representing all traditionally recognized subspecies. Population structure and phylogenomic analyses support four separately evolving giraffe lineages, which diverged 230-370 ka ago. These lineages underwent distinct demographic histories and show different levels of heterozygosity and inbreeding. Our results strengthen previous findings of limited gene flow and admixture among putative giraffe species and establish a genomic foundation for recognizing four species and seven subspecies, the latter of which should be considered as evolutionary significant units. Achieving a consensus over the number of species and subspecies in giraffe is essential for adequately assessing their threat level and will improve conservation efforts for these iconic taxa.
物种是生物学中最基本的分类单位，其划分对保护具有重要意义。自 20 世纪初以来，长颈鹿（Giraffa spp.）的分类已经提出了多种方案。然而，由于深入评估有限、亚种在圈养中杂交以及野生杂交个体的传闻报告，通常接受一个物种九个亚种的观点。在使用传统遗传标记的种群遗传研究表明至少有四个物种之后，长颈鹿的分类学受到了新的关注。这种观点引起了争议，为辩论奠定了基础。基因组学在物种划分和保护方面相对于传统遗传方法显著增强了我们对生物多样性和物种形成的理解。我们提供了极度濒危的努比亚长颈鹿（G. camelopardalis antiquorum）的高质量从头基因组组装，并对代表所有传统上公认亚种的 50 头长颈鹿进行了全面的全基因组分析。种群结构和系统基因组分析支持四个单独进化的长颈鹿谱系，它们在 230-370 千年前分化。这些谱系经历了不同的种群历史，表现出不同程度的杂合性和近亲繁殖。我们的研究结果加强了之前关于有限的基因流和杂交的发现，并为识别四个物种和七个亚种建立了基因组基础，后者应被视为进化上有意义的单位。在长颈鹿中达成对物种和亚种数量的共识对于充分评估其威胁程度至关重要，并将改善这些标志性类群的保护工作。
