Genetic diversity of the sea cucumber, Holothuria scabra in New Caledonia, Australia (Northern Territory) and Bali

Within-region genetic heterogeneity of Holothuria scabra populations in New Caledonia was examined through allozyme electrophoresis. Five locations, each separated by 60-130 km, were selected along the coast of New Caledonia and 2 replicate sites (8-23 km apart) were chosen within 4 of these locations on the west coast of the island. Only one site was selected on the northeast coast. Between 14 and 34 adult Holothuria scabra were collected from each site. A short section of the upper intestine (5-10 cm), without sediments, was dissected from each animal and stored in liquid nitrogen until analysed. Holothuria scabra samples from Bali (n=90) and Knocker Bay, Australia (n=47), and existing data from the western Pacific: Solomon Islands; Torres Strait; and the Queensland Coast (Upstart Bay and Hervey Bay) were compared with the data from New Caledonia to investigate larval connectivity over a wider geographic scale. Seven polymorphic enzyme loci were surveyed using allozyme electrophoresis: GPI, HK, MDH, PEP-1, PEP-2, PEP-3 and PGM. Basic analyses of genetic variability (allele frequencies, number of polymorphic loci, heterozygosity) were carried out. The allelic richness for each population was calculated. F statistics were calculated and genetic distance analyses, cluster analyses and Mantel tests were performed. This research was undertaken to improve understanding of the genetic differentiation between stocks of Holothuria scabra at different spatial scales so that the release of cultured juveniles in restocking programs can be planned in a responsible way to preserve the genetic diversity of existing stocks. Sampling sites in New Caledonia: A=Baie de Sainte-Marie; B= Ilot Maître; C=Ouano; D=Ilots Kundogi; E=Plateau de Béco; F=Pointe Pindaï; G=Pouangué; H=Ouaco; I=Récif Thaavaam (Ilot Cocotier).

本研究通过同工酶电泳（allozyme electrophoresis）技术，对新喀里多尼亚海域糙海参（Holothuria scabra）种群的区域内遗传异质性展开了检测。研究人员沿新喀里多尼亚海岸选取了5个采样点，各点间距为60~130 km；其中该岛西海岸的4个采样点内各设置了2个重复采样点（两点间距8~23 km），东北海岸仅设置了1个采样点。每个采样点采集了14~34头成年糙海参。从每头个体的前段肠管截取5~10 cm不含沉积物的组织，置于液氮中保存直至后续分析。为在更大地理尺度下探究幼体连通性，研究团队将新喀里多尼亚的糙海参样本数据，与来自巴厘岛（n=90）、澳大利亚诺克湾（Knocker Bay，n=47）的糙海参样本，以及西太平洋已公开的相关数据（所罗门群岛、托雷斯海峡、昆士兰海岸的厄普斯特湾与赫维湾）进行了对比分析。本次研究采用同工酶电泳技术，对7个多态性酶基因座进行了检测，分别为GPI、HK、MDH、PEP-1、PEP-2、PEP-3与PGM。研究开展了遗传变异相关的基础分析，包括等位基因频率、多态性基因座数量、杂合度等指标；同时计算了各群体的等位基因丰富度，并进行了F统计量、遗传距离分析、聚类分析以及Mantel检验。本研究旨在加深对不同空间尺度下糙海参种群间遗传分化的认知，以便合理规划增殖放流项目中养殖幼体的放流方案，从而有效保护现有种群的遗传多样性。新喀里多尼亚的采样点信息如下：A=圣玛丽湾（Baie de Sainte-Marie）；B=迈特尔岛（Ilot Maître）；C=瓦诺（Ouano）；D=昆多吉群岛（Ilots Kundogi）；E=贝科高原（Plateau de Béco）；F=潘达伊角（Pointe Pindaï）；G=普旺盖（Pouangué）；H=瓦科（Ouaco）；I=塔瓦姆礁（Récif Thaavaam，椰岛Ilot Cocotier）。