Relatedness inferred from
microsatellite genotypes as a tool for broodstock management of Japanese
flounder Paralichthys olivaceus
M. Sekino, T. Sugaya, M. Hara, N. Taniguchi-2004
Aquaculture, 233(1-4): 163-172
Abstract:
We propose here a possible way to retard the loss of
genetic variation in closed and non-pedigreed captive populations of
Japanese flounder Paralichthys olivaceus by using a
microsatellite-based kinship estimator (rxy). We explored
the utility of the estimator by applying the statistic to kinship
discrimination in a Japanese flounder hatchery strain (83 offspring). We
also investigated the effectiveness of minimal kinship selection (mk
selection), which conceptually gives a high priority to individuals with
rarer genotypes as broodstock parents, to minimize the loss of genetic
variations in the next generation. A nonparametric analysis revealed that
the difference of the pairwise rxy values estimated for
the offspring was highly significant between full-sib, half-sib, and
unrelated categories, although this statistic showed a wide range of
variations even within a kinship category. The mk selection based on
the kinship estimator gave a benefit in the retention of both allelic
diversity (number of alleles per locus) and gene diversity (unbiased
expected heterozygosity) in the fish selected from the offspring pool: this
approach, however, did not necessarily select unrelated fish, possibly
resulting in sib mating, it should thus be necessary to preclude the mating
between highly related individuals in the selected fish to minimize risk of
inbreeding.
(Tohoku National Fisheries Research Institute,
Fisheries Research Agency, Shinhama, Shiogama, Miyagi 985-0001, Japan,
e-mail: sekino@affrc.go.jp)