Population genetics of the fissiparous holothurians, Stichopus chloronotus and Holothuria atra, Torres Strait and La Reunion

About 50 individuals from each of 5 populations of the fissiparous holothurian species Stichopus chloronotus and 4 populations of Holothuria atra were collected from the Torres Strait and La Reunion in 1999 to compare patterns of asexual reproduction and to investigate connectivity between widely separated geographic regions.Polymorphic enzyme loci were surveyed using allozyme electrophoresis: PGM, GPI, HK, LP, PGD, PGM, VL in Holothuria atra; and HK, MPI, PGM, TPI, VL in Stichopus chloronotus.The proportions of asexual contributions was assessed from sexually produced individuals.UPMGA cluster analysis using Rogers' genetic distance was carried out. The aim of the study was to compare the importance of asexual reproduction between the two regions and between the two species, and to investigate connectivity between holothurian populations in the two oceans. Reef locations: Cumberland Reef no.3, Derder and Warrior Reefs in the Torres Strait; and Etang Sale, Planch Alizes, St. Leu and Trou d¿eau at La Reunion.

1999年，研究人员从托雷斯海峡（Torres Strait）与留尼旺岛（La Reunion）采集样本：5个裂体繁殖海参物种绿刺参（Stichopus chloronotus）种群，以及4个黑海参（Holothuria atra）种群，每个种群采集约50个个体，旨在对比二者的无性繁殖模式，并探究相隔遥远的地理区域间的种群连通性。采用同工酶电泳（allozyme electrophoresis）技术对多态酶基因座进行检测：黑海参的检测基因座包括PGM、GPI、HK、LP、PGD、PGM、VL；绿刺参的检测基因座包括HK、MPI、PGM、TPI、VL。研究人员通过有性繁殖个体的遗传特征，评估了无性繁殖的贡献占比。基于罗杰斯遗传距离（Rogers' genetic distance），采用UPMGA聚类分析开展了相关研究。本研究的核心目标为：对比两个地理区域以及两个海参物种间无性繁殖的重要性差异，并探究两大洋中海参种群的连通性。本次研究的礁区采样点包括：托雷斯海峡的坎伯兰3号礁（Cumberland Reef no.3）、德尔德礁与沃里尔礁；留尼旺岛的埃唐萨莱（Etang Sale）、普朗阿利泽（Planch Alizes）、圣勒（St. Leu）与特鲁多水礁（Trou d'eau）。