Genetic variation in a closed line of the white shrimp Litopenaeus vannamei (Penaeidae)

Abstract

The culture of the marine shrimp Litopenaeus vannamei has recently boosted the Brazilian shrimp industry. However, it is well known that selection methods based solely on phenotypic characteristics, a reduced number of breeders and the practice of inbreeding may promote a significant raise in the genetic similarity of the captive populations, leading to greater disease susceptibility and impairing both the growth and final size of the shrimps. We used four microsatellite loci to investigate genetic variation in three generations (F 5 , F 6 and F 7 ) of a closed and reared L. vannamei lineage. Although an accentuated heterozygosis deficit was detected, we also observed that the captive propagation of this lineage did not lead to a significant loss of genetic variability over the three generations studied. One possible reason for this is that the breeding conditions of this lineage were good enough to prevent any significant loss of genetic variability. However, three generations may have been insufficient to produce detectable changes in genetic frequencies in the loci studied. Alternatively, the microsatellite loci may have been non-neutral (biased) and related to the conditions in which the shrimps were kept, resulting in a similar allele pool in respect to these four microsatellites over the three generations studied. Any generalizations regarding microsatellite variation in closed shrimp lines may thus be incomplete and should be carefully analyzed.

Genetic diversity status of Pacific white shrimp (Litopenaeus vannamei) using SSR markers in Iran

“…The specific loci were selected from the literature as the most highly diverse for this species (Cruz et al 2002(Cruz et al , 2004Valles-Jiménez et al 2005;Machado-Tamayo 2006;Garcia and Alcivar-Waren 2007;Luvesuto et al 2007). We had 6 and 4 % reduction of H o in Amiri-Gomishan (0.479-0.450) and Amiri-Gorgeaj (0.479-0.458) populations that represent a 5.4 and 3.6 % increase in inbreeding, respectively.…”

Hsp70 gene polymorphisms in farmed marine shrimp Litopenaeus vannamei populations exposed to white spot disease and infectious myonecrosis

“…Using microsatellites, Lima et al (2008) reported F IS ranging from 013 to 0.39 in L. vannamei from Bahia State (Northeastern Brazil). Other studies conducted with L. vannamei populations from Brazilian post-larvae production laboratories showed F IS ranging from 0.00 to 0.38 (Luvesuto et al, 2007;Lima et al, 2010;Maggioni et al, 2013). Considering the history of geographical isolation, the higher F IS values observed in populations Lv-A and Lv-B from Southern Brazil are likely related to inbreeding.…”

Use and exchange of genetic resources of penaeid shrimps for food and aquaculture

“…Reductions in genetic variation as time under culture have increased have been reported in P. japonicus (Sbordoni et al 1986(Sbordoni et al , 1987, P. chinensis (He et al 2004;Li et al 2006b), P. stylirostris (Bierne et al 2000;Goyard et al 2003) and P. vannamei ), but the decrease over time is highly variable, with many populations held for more generations showing less loss than populations held for less time . No decline over time was observed for stocks of P. chinensis (Zhang et al 2004) or P. vannamei (Cruz et al 2004;Soto-Hernandez & Grijalva-Chon 2004;Luvesto et al 2007).…”