Genus-wide paleogenetic analysis of Middle to Late Pleistocene extinct straight-tusked elephants (Palaeoloxodon) to infer phylogeography and patterns of admixture

对中更新世至晚更新世灭绝的直牙象（Palaeoloxodon）进行全属古遗传学分析，以推断系统发育地理学和混合模式

• 批准号: 442555017
• 负责人: Dr. Sina Baleka
• 金额: --
• 依托单位: Department of Pathology and Molecular Medicine
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/442555017?language=en
• 关键词: Genus; wide; paleogenetic; analysis; Middle

The largely unknown extinct straight-tusked elephants (Palaeoloxodon) once roamed wide parts of Africa and Eurasia. The genus is part of the family Elephantidae, which also encompasses the three living elephant species. Palaeoloxodon specimens have been proven challenging to place in the phylogenetic tree using morphological features. Additionally, they display features complicating paleogenetic (= ancient DNA = aDNA) research, namely a distribution in warm climates and a relatively high age, which both are detrimental for DNA preservation. However, the few studies carried out revealed surprising results, severely altering our view of the evolution of Elephantidae. The DNA sequences generated, which are some of the oldest from non-permafrost regions, showed that Palaeoloxodon belonged to a different branch in the phylogenetic tree than previously believed. The single available high-coverage genome revealed that this Palaeoloxodon specimen showed high levels of admixture with two different lineages within the Elephantidae. Clearly, more data is needed, extending the geographical range of the current samples (four from Germany and one from Italy) and also the depth of information obtained. The proposed research will generate the first genus-wide paleogenetic overview over Palaeoloxodon, determining the number and distribution of species. Estimations of divergence times, population size changes, and events of admixture during the Pleistocene hold the opportunity to link these events to climatic cycles, helping our understanding of the connection between climate change and species reactions.

大部分未知的灭绝直齿象（Palaeoloxodon）曾经漫游在非洲和欧亚大陆的大部分地区。该属是大象科的一部分，该科也包括三种现存的大象物种。古齿象标本已被证明具有挑战性的地方，在系统发育树使用形态特征。此外，它们还显示出使古基因（=古DNA = aDNA）研究复杂化的特征，即分布在温暖的气候中和相对较高的年龄，这两者都不利于DNA的保存。然而，为数不多的研究揭示了令人惊讶的结果，严重改变了我们对大象科进化的看法。所产生的DNA序列是来自非永久冻土地区的最古老的DNA序列，表明古牛齿龙在系统发育树中属于与以前认为的不同的分支。单一可用的高覆盖率的基因组显示，这Palaeoloxodon标本表现出高水平的混合物与两个不同的谱系内的象。显然，需要更多的数据，扩大目前样本的地理范围（四个来自德国，一个来自意大利），并扩大所获得信息的深度。这项拟议的研究将产生第一个全属的Palaeoloxodon古遗传概述，确定物种的数量和分布。对更新世期间的分歧时间、种群规模变化和混合事件的估计，有机会将这些事件与气候周期联系起来，有助于我们理解气候变化与物种反应之间的联系。