Levels and patterns of genetic variation in an Asian horseshoe crab species, <i>Tachypleus gigas</i> Müller, from the Malay Peninsula

Horseshoe crabs are one of the oldest living organisms that still exist today. Given the overexploitation of horseshoe crabs around the world, and the lack of information on their populations, it is crucial that genetic variation studies are done to assess their levels and patterns of genetic variation for continuous monitoring and management of their populations. Here, five populations of the Asian horseshoe crab <i>Tachypleus gigas</i> sampled from along the coasts of the Malay Peninsula were studied using simple-sequence repeat (SSR) and inter-simple-sequence repeat (ISSR) markers. Different results were obtained using the two different types of markers in terms of the levels of genetic variation estimated, but both concurred that most of the genetic variations were distributed at the individual level rather than among populations of the species. Inbreeding was also observed using the SSR data, although the presence of null alleles could have influenced the estimation. Finally, both marker types revealed that <i>T. gigas</i> could have been subjected to the land barrier effect of the Malay Peninsula that causes populations from the Indian Ocean to be genetically differentiated from the populations from the South China Sea.

鲎（horseshoe crab）是现存最古老的活化石类群之一。鉴于全球范围内鲎资源被过度开发，且其种群相关信息匮乏，开展遗传变异研究以评估其遗传变异水平与模式，对于实现种群的持续监测与管理至关重要。本研究以马来半岛沿岸海域采集的5个亚洲鲎（Asian horseshoe crab，学名*Tachypleus gigas*）种群为研究对象，采用简单序列重复（simple-sequence repeat，SSR）和简单序列重复区间（inter-simple-sequence repeat，ISSR）分子标记开展遗传分析。两种分子标记在遗传变异水平的估算结果上存在差异，但二者均一致表明，该物种的绝大多数遗传变异分布于个体内部，而非种群之间。基于SSR标记的数据还检测到了近交现象，不过无效等位基因（null alleles）的存在可能对估算结果造成了干扰。最终，两种分子标记均揭示，巨鲎可能受到马来半岛陆地屏障效应的影响，致使印度洋海域种群与南海海域种群产生遗传分化。

搜集汇总

背景与挑战

背景概述

该数据集研究了马来半岛沿海亚洲鲎物种Tachypleus gigas的遗传变异水平与模式，使用SSR和ISSR标记分析五个种群。研究发现遗传变异主要分布在个体层面，并观察到近交现象，同时揭示了马来半岛陆地屏障效应导致印度洋与南海种群遗传分化。