African Journal of Biotechnology Vol. 4 (12), pp. 1362-1367, December 2005          
ISSN 1684–5315 © 2005 Academic Journals

Full Length Research Paper

Assessment of the genetic diversity in five generations of a commercial broodstock line of Litopenaeus vannamei shrimp

Patrícia Domingues de Freitas and Pedro Manoel Galetti Jnr.

Departamento de Genética e Evolução, Universidade Federal de São Carlos, Caixa Postal 676, 13565-905 - São Carlos, SP, Brazil (correspondence to P.D.F.)

*Corresponding authors E-mail: patdf@iris.ufscar.br; Tel: 55 16 2608309; Fax: 55 16 260 8306.

Accepted 2 August, 2005

Genetic variation among and within five generations of an inbred commercial captive line of Litopenaeus vannamei and genetic distance among them were evaluated by random amplified polymorphic DNA (RAPD), using descriptive and genetic similarity analyses for dominant markers at single- and multi-populational level. One hundred individuals were analyzed and 56 polymorphic loci were identified with a set of six primers screened in a painel of 38 decamer primers tested. The values obtained for F₅, F₆, F₇, F₈ and F₉ generations revealed a progressive increasing of genetic similarity throughout the five stocks, confirmed by Nei genetic diversity analysis, which values decreased from 0.27 to 0.22 at F₅ and F₉, respectively. Significant allele frequency differences were observed at most analyzed loci. Strong correlation (R² = 0.9845) was observed between genetic similarity and generation time, and genetic similarity could reach closer to 100% at 18-19 generation of this line.

Key words: Litopenaeus vannamei, genetic diversity, genetic drift, inbreeding, RAPD.