A phylogenetic study of the origin of the domestic pig estimated from the near-complete mtDNA genome
A phylogenetic study of the origin of the domestic pig estimated from the near-complete mtDNA genome
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DOI：
10.1007/s002390010158
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发表时间：
2001-03-01
影响因子：
3.9
通讯作者：
Andersson, L
中科院分区：
文献类型：
--
作者：
Kijas, JMH;Andersson, L
从2头家猪（1头中国梅山猪和1头瑞典长白猪）和2头欧洲野猪中测定了接近完整的猪mtDNA基因组序列（15，997 bp）。这些序列与先前发表的代表瑞典家猪的序列一起进行了分析。序列形成三个：不同的分支，表示为A，E1和E2，它们之间有相当大的序列差异（0.8-1.2%）。这些结果证实了我们之前的研究（仅基于细胞色素B基因和控制区的序列），并提供了令人信服的证据，证明猪的驯化必须发生在野猪的亚洲和欧洲亚种之间。我们估计进化枝A（发现于中国梅山猪）和进化枝El（发现于欧洲家猪）发生分歧的时间大约是在现在之前90万年，早在大约9000年前的驯化之前。序列之间的核苷酸取代的模式是在很好的协议与以前的种间比较的哺乳动物mtDNA;最低的取代率观察到在非同义位点的蛋白质编码基因，在tRNA和rRNA基因，而最高的利率观察到在同义位点和控制区。在一些主要的欧洲品种（大白色和长白猪）中存在亚洲进化枝A，这很可能反映了18世纪和19世纪亚洲种质向欧洲种群的基因渗入。如果父源遗传和重组发生频率较低，那么100+代的这种不同mtDNA单倍型的共存预计会导致重组单倍型的存在。我们没有发现这样的重组事件的证据，在有限的样本研究到目前为止。
The near-complete pig mtDNA genome sequence (15,997 bp) was determined from two domestic pigs (one Chinese Meishan and one Swedish Landrace) and two European wild boars. The sequences were analyzed together with a previously published sequence representing a Swedish domestic pig. The sequences formed three:distinct clades, denoted A, E1, and E2, with considerable sequence divergence between them (0.8-1.2%). The results confirm our previous study (based on the sequence of the cytochrome B gene and the control region only) and provide compelling evidence that domestication of pigs must have occurred from both an Asian and a European subspecies of the wild boar. We estimated the time since the divergence of clade A (found in Chinese Meishan pigs) and El (found in European domestic pigs) at about 900,000 years before present, long before domestication about 9000 years ago. The pattern of nucleotide substitutions among the sequences was in good agreement with previous interspecific comparisons of mammalian mtDNA; the lowest substitution rates were observed at nonsynonymous sites in protein-coding genes, in the tRNA and rRNA genes, while the highest rates were observed at synonymous sites and in the control region. The presence of Asian clade A in some major European breeds (Large White and Landrace) most likely reflects the documented introgression of Asian germplasm into European stocks during the 18th and 19th centuries. The coexistence of such divergent mtDNA haplotypes for 100+ generations is expected to lead to the presence of recombinant haplotypes if paternal transmission and recombination occur at a low frequency. We found no evidence of such recombination events in the limited sample studied so far.