Abstract

Inbreeding as negative factor perhaps promote a significant increase of the genetic similarity of the captive populations, consequently leading to greater disease susceptibility and impairment of both the growth and final size of the shrimps. Therefore evaluating genetic diversity and inbreeding required for improvement of brood stock management will assist shrimp breeders to minimize or avoid inbreeding coefficient. The objective of this study was to assess the genetic diversity of intensive cultured and wild tiger shrimp Penaeus monodon (Fabricius) in Malaysia using six microsatellite markers (CSCUPmo1,CSCUPmo2,CSCUPmo3,CSCUPmo4,CSCUPmo6 and CSCUPmo7). The mean numbers of allele, observed heterozygosis, and polymorphism information content (PIC) index were calculated. The observed allele’s sizes at the investigated loci were similar to those of previous reports. The number of alleles yielded by all microsatellites ranged from 2 to 6 alleles. The highest and the lowest effective number of alleles were found in CSCUPmo1 (4.16) and CSCUPmo7 (1.3), respectively. The most frequent alleles (MFA) forCSCUPmo1, CSCUPmo2, CSCUPmo3, CSCUPmo4, CSCUPmo6 and CSCUPmo7 bp were 259, 165, 181, 242, 206 and 218 bp, respectively. Brood stock showed lower genetic diversity value than wild population. However, with an observed heterozygosity (H_obs) below expectations it would be necessary to introduce cross breeding among hatcheries to reduce the risk of inbreeding depression. Microsatellite markers analysis was able to characterize the genetic divergence between the brood stocks and wild population and could be helpful tools for defining better management strategies of these P. monodon (Fabricius) in Malaysia.

Keywords: Inbreeding, Penaeus monodon (Fabricius), Malaysia, microsatellite markers.

Abbreviation

dNTP, Dinucleotide triphosphate; H_O, observed heterozygosity;PCR, polymerase chain reaction; MFA, most frequent alleles; SSRs, simple sequence repeats; PIC, polymorphism information content.