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

Full description

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).

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Maintenance and Update Frequency: notPlanned

Statement: Statement: The methods used for electrophoresis are described in:Uthicke S and Benzie JAH (1999) Allozyme variation as a tool for bêche-de-mer fisheries management: a study on Holothuria scabra (sandfish). SPC Bêche-de-mer Inf. Bull. 12: 18-23.andUthicke, S and Benzie, JAH (2001) Restricted gene flow between Holothuria scabra (Echinodermata: Holothuroidea) populations along the northeast coast of Australia and the Solomon Islands. Mar. Ecol. Prog. Ser. 216: 109-117.Statistical packages and methods used for statistical analyses were as follows:El Mousadik A and Petit RJ (1996) High level of genetic differentiation for allelic richness among populations of the argan tree [Argani spinosa (L.) Skeels] endemic to Morocco. Theor. Appl. Genet. 92: 832-839.Goudet J (2001) FSTAT, a program to estimate and test gene diversities and fixation indices (version 2.9.3). Available from http://www.unil.ch/izea/softwares/fstat.htmlHochberg Y (1988) A sharper Bonferroni procedure for multiple tests of significance. Biometrika, 75: 800-802.Miller MP (1997) Tools for population genetic analyses (TFPGA 1.3): a windows programme for the analyses of allozyme and molecular population genetic data. Computer software distributed by the author. Available from http://bioweb.usu.edu/mpmbio/Raymond M and Rousset F (1995) An exact test for population differentiation. Evolution, 49: 1280-1283.Rogers JS (1972) Measures of genetic similarity and genetic distance. In: Studies in genetics. VII Publ. No. 7213. University of Texas, Austin, Texas, pp 145-154.Slatkin M (1993) Isolation by distance in equilibrium and non-equilibrium populations. Evolution 47: 264-279.Swofford DL and Selander RB (1981) BIOSYS-1: a fortran program for the comprehensive analysis of electrophoretic data in population genetics and systematics. J. Hered. 72: 281-283.Weir BS and Cockerham CC (1984) Estimating F-statistics for the analysis of population structure. Evolution, 38: 1358-1370.

Notes

Credit
Uthicke, Sven, Dr (Principal Investigator)