瑞典研究人员近日表示,他们已经进一步证实了目前世界上所有种类的狗都起源于东亚南部某地驯养的狼,而非之前另一项研究所暗示的中东起源论。其论文"Comprehensive study of mtDNA among Southwest Asian dogs contradicts independent domestication of wolf, but implies dog–wolf hybridization"发表于最新一期的《生态学与进化》杂志网络版上。
瑞典皇家理工学院(KTH Royal Institute of Technology)的进化遗传学研究员彼得莎沃莱恩博士(Dr Peter Savolainen)表示,他们进行的一项新的基因研究提供了强有力的证据,证实亚洲的长江以南地区是主要的,可能也是唯一的狼被人类驯化的地区。
遗传学、形态和习性数据清楚地表明,狗是狼的后裔,但一直无法证明狗的起源地。莎沃莱恩说:“现在我们对脱氧核糖核酸(DNA)Y染色体的分析证实,狼首次在亚洲的长江以南地区被驯养,我们称之为ASY地区,在中国南部或东南亚。线粒体DNA的Y染色体数据支持我们之前的一项研究。这两项研究提供了非常有力的证据,表明狗起源于ASY地区。”
最近在《自然》杂志上发表的考古资料和遗传研究称,狗起源于中东。但莎沃莱恩拒绝接受这一观点。他说:“因为这些研究没有包括从ASY地区采集的DNA样本,ASY的证据被忽视了。”
彼得 莎沃莱恩博士和博士生马蒂亚斯 奥斯卡森(Mattias Oskarsson)以及中国同事对来自世界各地的公狗进行DNA分析,并识别出10组不同类型的DNA。他们的研究结果发表在《科学遗传》杂志上。他们在世界其它地区的狗身上只找到大约一半的基因库,而只有ASY地区具有最完整的遗传多样性,找到所有的10组DNA。莎沃莱恩说:“这表明,在世界所有其它地区的基因库最有可能来自ASY地区。我们的研究结果证实,长江以南地区是最重要的,可能是唯一的狼被驯化的地区,而且大量的狼被驯化。”
新的研究成果最近发表在《生态学和进化》杂志上,莎沃莱恩、博士生阿尔曼 阿达兰( Arman Ardalan),以及伊朗和土耳其科学家对狗的线粒体DNA进行了全面的研究,重点针对中东的狗。由于线粒体DNA只能从大多数物种的母系继承,它在进化关系研究中特别有用。莎沃莱恩说:“由于其它研究表明,狼驯化是在中东,为了确保我们的研究没有失误,所以我们重点研究中东的狗,但我们发现没有任何迹象显示狗起源于中东。”
此次研究不仅表明了犬类具有唯一的地理起源以及第一只狗来自于东亚南部,还揭示了犬类的诞生源于对野生狼的大量驯养。在他们的研究中,研究人员还发现在某些地区出现过狗和狼之间的杂交现象,包括中东地区。(生物谷Bioon.com)
doi:10.1002/ece3.35
PMC:
PMID:
Comprehensive study of mtDNA among Southwest Asian dogs contradicts independent domestication of wolf, but implies dog–wolf hybridization
Ardalan, Arman; Kluetsch, Cornelya F. C.; Zhang, Ai‐ing; Erdogan, Metin; Uhlén, Mathias; Houshmand, Massoud; Tepeli, Cafer; Ashtiani, Seyed Reza Miraei; Savolainen, Peter
Studies of mitochondrial DNA (mtDNA) diversity indicate explicitly that dogs were domesticated, probably exclusively, in southern East Asia. However, Southwest Asia (SwAsia) has had poor representation and geographical coverage in these studies. Other studies based on archaeological and genome-wide SNP data have suggested an origin of dogs in SwAsia. Hence, it has been suspected that mtDNA evidence for this scenario may have remained undetected. In the first comprehensive investigation of genetic diversity among SwAsian dogs, we analyzed 582 bp of mtDNA for 345 indigenous dogs from across SwAsia, and compared with 1556 dogs across the Old World. We show that 97.4% of SwAsian dogs carry haplotypes belonging to a universal mtDNA gene pool, but that only a subset of this pool, five of the 10 principal haplogroups, is represented in SwAsia. A high frequency of haplogroup B, potentially signifying a local origin, was not paralleled with the high genetic diversity expected for a center of origin. Meanwhile, 2.6% of the SwAsian dogs carried the rare non-universal haplogroup d2. Thus, mtDNA data give no indication that dogs originated in SwAsia through independent domestication of wolf, but dog–wolf hybridization may have formed the local haplogroup d2 within this region. Southern East Asia remains the only region with virtually full extent of genetic variation, strongly indicating it to be the primary and probably sole center of wolf domestication. An origin of dogs in southern East Asia may have been overlooked by other studies due to a substantial lack of samples from this region.