Isozyme analysis and genetic variability among semiterrestrial crabs of the family Camptandriidae (Decapoda: Brachyura: Ocypodoidea) from the coastal areas of Pakistan

Abstract

Genetic diversity within different Camptandriid species and their populations have been investigated using isozyme electrophoresis from the North Arabian coast of Pakistan. Patterns of a total of eight isozymes including Amylase, Carbonate anhydrates, Catalase, Creatine kinase, Glucose 6 phosphate dehydrogenase, Octanol dehydrogenase, Peroxidase and a general protein were analyzed within three Camptandriid crab species (Manningis arabicum (DA Jones & Clayton, 1983), Opusia indica (Alcock, 1900) and Nasima dotilliformis (Alcock, 1900)) and their populations. The calculated mean number of alleles per locus was 1.26±0.1; the percentage of polymorphic loci per population ranged between 7.45 – 33.3 %; the observed heterozygosity ranged between 0.033 – 0.124; and the expected heterozygosity ranged from 0.032 – 0.14. Intraspecific studies showed that the coefficient of gene differentiation among populations was low (FST = 0.032), indicating that only 3.2 % of the total genetic diversity comes from inter-population differences; while the remaining 96.8 % comes from intra-population differences. The intraspecific genetic distance was calculated as 0.000 – 0.008 (average = 0.002), and the gene flow among the populations of O. indica and N. dotilliformis was calculated as 1.57 to 0.824, respectively. Interspecific Nei's genetic distance calculated using allele frequencies were 0.474 between N. dotilliformis and M. arabicum, 0.505 between N. dotilliformis and O. indica, and 0.658 between O. indica and M. arabicum which showed that O. indica and M. arabicum is genetically closer species.