Bon Céline, Caudy Nicolas, de Dieuleveult Maud, Fosse Philippe, Philippe Michel, Maksud Frédéric, Beraud-Colomb Eliane, Bouzaid Eric, Kefi Rym, Laugier Christelle, Rousseau Bernard, Casane Didier, van der Plicht Johannes, Elalouf Jean-Marc
Service de Biologie Intégrative et Génétique Moléculaire, Institut de Biologie et Technologies de Saclay, Commissariat à l'Energie Atomique Saclay, 91191 Gif-sur-Yvette Cedex, France.
Proc Natl Acad Sci U S A. 2008 Nov 11;105(45):17447-52. doi: 10.1073/pnas.0806143105. Epub 2008 Oct 27.
Retrieving a large amount of genetic information from extinct species was demonstrated feasible, but complete mitochondrial genome sequences have only been deciphered for the moa, a bird that became extinct a few hundred years ago, and for Pleistocene species, such as the woolly mammoth and the mastodon, both of which could be studied from animals embedded in permafrost. To enlarge the diversity of mitochondrial genomes available for Pleistocene species, we turned to the cave bear (Ursus spelaeus), whose only remains consist of skeletal elements. We collected bone samples from the Paleolithic painted cave of Chauvet-Pont d'Arc (France), which displays the earliest known human drawings, and contains thousands of bear remains. We selected a cave bear sternebra, radiocarbon dated to 32,000 years before present, from which we generated overlapping DNA fragments assembling into a 16,810-base pair mitochondrial genome. Together with the first mitochondrial genome for the brown bear western lineage, this study provides a statistically secured molecular phylogeny assessing the cave bear as a sister taxon to the brown bear and polar bear clade, with a divergence inferred to 1.6 million years ago. With the first mitochondrial genome for a Pleistocene carnivore to be delivered, our study establishes the Chauvet-Pont d'Arc Cave as a new reservoir for Paleogenetic studies. These molecular data enable establishing the chronology of bear speciation, and provide a helpful resource to rescue for genetic analysis archeological samples initially diagnosed as devoid of amplifiable DNA.
从已灭绝物种中获取大量遗传信息已被证明是可行的，但完整的线粒体基因组序列仅针对几百年前灭绝的恐鸟以及更新世物种（如猛犸象和乳齿象）进行了解码，这两种物种都可以从永久冻土中的动物样本进行研究。为了扩大可用于更新世物种的线粒体基因组的多样性，我们将目光转向了洞熊（Ursus spelaeus），其仅存的遗骸为骨骼元素。我们从法国肖维 - 蓬达尔克的旧石器时代彩绘洞穴中采集了骨骼样本，该洞穴展示了已知最早的人类绘画，并且包含数千具熊的遗骸。我们选择了一块距今32000年的洞熊胸骨，从中生成了重叠的DNA片段，组装成一个16810个碱基对的线粒体基因组。连同棕熊西部谱系的首个线粒体基因组一起，这项研究提供了一个经过统计学验证的分子系统发育树，评估洞熊是棕熊和北极熊进化枝的姐妹分类群，推断其分化时间为160万年前。随着首个更新世食肉动物线粒体基因组的完成，我们的研究将肖维 - 蓬达尔克洞穴确立为古遗传学研究的新资源库。这些分子数据有助于确定熊物种形成的时间顺序，并为抢救最初被诊断为缺乏可扩增DNA的考古样本进行遗传分析提供了有用的资源。
