Allozyme genetic
analysis in hatchery strains and wild blue shrimp, Penaeus (Litopenaeus)
stylirostris (Stimpson), from the Gulf of California
J. Ramos-Paredes, J.M. Grijalva-Chon-2003
Aquaculture
Research, 34(3):
221
Abstract:
We conducted a population genetic analysis
of Penaeus stylirostris to describe the genetic variability in two
wild samples (Guaymas and Peñasco) and in two cultivated strains (A and B),
and to determine the relationship among samples. Seventeen enzymatic systems
and general proteins were used to visualize 31 loci. Of the 31 loci, 11
polymorphic loci (35%) were detected in all the organisms, with an average
heterozygosity of 0.10 and an average of 1.8 per locus. There were no
significant differences among the four samples of observed heterozygosity or
percentage of polymorphic loci. According to Hardy-Weinberg, both cultivated
strains showed disequilibrium in more loci than the wild samples. Guaymas
showed linkage disequilibrium in five pairs of polymorphic loci, Peñasco
samples in two pairs, A in seven pairs, and B in nine pairs. Peñasco and
both cultivated lineages showed evidence of recent reductions in their
effective populations size. Based on the comparisons of Fst
values, and the distribution of the allelic frequencies, the cultivated
strains were significantly different from the two wild populations. There is
evidence that strain B originated from A and the discrepancies between the
strains are probably the result of genetic drift and a founder effect.
(Universidad de Sonora, Departamento de
Investigaciones Científicas y Tecnológicas, Rosales y Niños Héroes s/n,
Hermosillo, Sonora, Mexico 83000, e-mail of J.M. Grijalva-Chon: mgrijal@guayacan.uson.mx)