法国原子能委员会和法国国家科研中心研究人员最近通过分析洞熊的细胞基因组后发现，这种动物160万年前与现存的棕熊拥有共同祖先。
这两家机构在一份公报中介绍说，距今30万年到1.5万年前，洞熊生活在欧洲和中东地区，随后由于气候变化和人类狩猎等原因而灭绝。为了对这种庞大的动物有更深入的了解，科学家们对在法国南部阿尔代什省岩洞中发现的一块洞熊骨进行了DNA检测，并获得了完整的基因组数据。基因组内的线粒体能够为人们提供详细的动物机体演化信息，通过它可以判断出洞熊与棕熊何时发生了分化。
科学家们分析后推断，洞熊与棕熊在160万年前发生分化，此前，它们与北极熊都拥有同一个祖先。
这一研究成果已发表在最新一期美国《国家科学院院刊》上。（生物谷Bioon.com）
生物谷推荐原始出处：
Proceedings of the National Academy of Sciences，doi: 10.1073/pnas.0806143105，Céline Bon，Jean-Marc Elalouf
Deciphering the complete mitochondrial genome and phylogeny of the extinct cave bear in the Paleolithic painted cave of Chauvet
Céline Bona, Nicolas Caudya, Maud de Dieuleveulta, Philippe Fosseb, Michel Philippec, Frédéric Maksudd, éliane Beraud-Colombe, Eric Bouzaide, Rym Kefie, Christelle Laugierf, Bernard Rousseauf, Didier Casaneg, Johannes van der Plichth, and Jean-Marc Elaloufa,i,1
aService de Biologie Intégrative et Génétique Moléculaire,
fService de Chimie Bioorganique et de Marquage, Institut de Biologie et Technologies de Saclay, Commissariat à l'énergie Atomique Saclay, 91191 Gif-sur-Yvette Cedex, France;
bCentre National de la Recherche Scientifique Unité Mixte de Recherche 5608, Université Toulouse le Mirail, 31058 Toulouse Cedex 1, France;
cMuséum d'Histoire Naturelle, 28 Boulevard des Belges, 69000 Lyon, France;
dService Régional de l'Archéologie, 32 Rue de la Dalbade, BP811 31080 Toulouse cedex 6, France;
eInstitut National de la Santé et de la Recherche Médicale U600, H?pital Sainte Marguerite, 270 Boulevard Sainte Marguerite, 13009 Marseille, France;
gLaboratoie Evolution, Génomes et Spéciation, Unité Propre de Recherche 9034 Centre National de la Recherche Scientifique, 91198 Gif-sur-Yvette Cedex, France;
hRadiocarbon Laboratory, Groningen University, Nijenborgh 4, 9747 AG Groningen, The Netherlands; and
iFaculty of Archaeology, Leiden University, P.O. Box 9515, 2300 RA Leiden, The Netherlands
Abstract
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.
