青岛近海路氏双髻鲨群体遗传学分析

GENETIC STUDY ON SPHYRNA LEWINI FROM QINGDAO COASTAL WATERS

研究采集了青岛近海23尾路氏双髻鲨(Sphyrna lewini),通过线粒体DNA控制区片段对其遗传多样性进行分析。研究结果显示:在23个个体的控制区序列上存在13个变异位点,未检测到插入/缺失位点;检测到7个单倍型,其中3个为个体共享单倍型(Hap1、Hap3和Hap5),4个为个体独有单倍型;青岛近海路氏双髻鲨呈现中等水平的单倍型多样度和较低的核苷酸多样度;与已报道的日照、霞浦群体间的遗传分化指数Fst值分别为–0.0571和–0.0328,表明青岛群体与其他两个群体间不存在显著差异。以Sphyrna zygaena为外群构建NJ系统树显示本研究中7个单倍型共分成两支,分别与来自太平洋、印度洋的单倍型类群聚类。中国近海的路氏双髻鲨作为一个具有较低遗传多样性的濒危物种,其资源保护更应该引起足够的重视。

The scalloped hammerhead shark, Sphyrna lewini, is a small to medium-sized shark that circumglobally distributes along continental margins and oceanic islands in tropical waters. It has been listed as one globally endangeredspecies by IUCN because of continuous resource recession by habitat degradation and influence of human activities.The present study analyzed mitochondrial DNA sequences of a total of 23 specimens collected from Qingdao coastalwaters, and found 13 variable sites in the 548 bp fragments without indel/deletion. These polymorphic sites defined 7haplotypes, 3 of them （Hap1, Hap3 and Hap5） were different individuals and the other 4 haplotypes were unique forone individual. Moderate haplotype diversity and low nucleotide diversity were detected for Qd population. There wasno genetic differentiation between Qd and other reported two populations, and Fst were –0.0571 and –0.0328, respectively. Haplotypes from Chinese coastal waters were clustered into two clades with haplotypes from the Pacific and In-dian Ocean by the topology of the NJ tree rooted with the out-group S. zygaena. More attentions should be paid to resource protection for Sphyrna lewini with, and the endangered species （Sphyrna lewini） from Chinese coastal watersshould be considered one population, which need greater resource protection because of low genetic diversity.