陇东黄土高原石鸡的分子系统地理结构

摘要

Using polymerase chain reaction and direct sequencing methods, a total of 491 nucleotides of the mitochondrial DNA (mtDNA) control-region genes were sequenced in 78 chukar partridges Alectoris chukar collected from eight populations throughout the Loess Plateau of eastern Gansu to reconstruct the molecular phylogeographic structure. The 24 variable sites defined 25 haplotypes. The eight populations diverged from common ancestor because they shared one haplotype C1. Part populations shared some other five haplotypes showed there was gene flow among the populations. The 25 haplotypes mixed in a neighbour-joining phylogenetic tree and did not cluster into separated branch in the light of the population situation; however, they clustered into two branches. Phylogenetic analysis of the haplotype network identified two groups, respectively stemming from haplotype C1 and haplotype C2 that were at the center of two star-like topologies.The genetic variation was significant different between the two groups, which had been isolated in the historical period.The mitochondrial DNA sequences suggested the existence of a phylogeographic structure among chukar partridge populations in the Plateau, resulting from the synergistic affection of glaciers, debris flow and human activities since the middle of the Pleistocene. The molecular phylogeographical structure of the chukar partridge in this region belonged to "phylogenetic continuity, partly spatial separation" geographical pattern [Acta Zoologica Sinica 50 (4): 576- 582, 2004].%本文运用聚合链式反应和直接测序的方法测定陇东黄土高原8个石鸡(Alectoris chukar)地理种群78个样本的mtDNA控制区491 bp,建立其分子系统地理结构.78个样本共发现24个变异位点,25种单倍型.8个地理种群共享单倍型C1,6个种群共享单倍型C2,种群间有一定的基因交流.8个地理种群的25种单倍型在NJ树中相互混杂,没有形成独立的地理结构,但聚成两个分支.单倍型网络图显示25种单倍型聚成两个星状的集群,分别以单倍型C1和C2为中心.这两个群间的遗传差异显著.陇东黄土高原石鸡的系统地理结构属于"系统发生连续,具有部分空间隔离"的地理格局.这种地理格局是更新世冰川、泥石流和人类活动共同作用的结果[动物学报50(4):576-582,2004].