Parentage assignment of stocked black sea bream <Emphasis Type="Italic">Acanthopagrus schlegelii</Emphasis> in Hiroshima Bay using microsatellite DNA markers

The genetic contribution of 51 broodstock, comprising 29 females and 22 males, reared at Hiroshima City Marine Products Promotion Center for the production of stocked black sea bream was monitored during two consecutive years using seven microsatellite DNA loci. The high discrimination ability of these markers was reflected in the polymorphic identification content (PIC=0.831), the exclusion probability (Q≈1), and the low probability of identity index (I=3.635⁻¹⁰). The total number of breeders contributing to the mating process was estimated at 32 (62.7%) in 2000 and 30 (58.8%) in 2001. On pedigree reconstruction, 69.3% of the offspring were successfully assigned to a single broodstock pair. Loss of alleles accounted for 16.9% during seed production; nevertheless, 90.9% of males and 69.0% of females participated in the mating process. Based on microsatellite genetic tagging, 58.9% of the fish sampled during the two months after release were identified as hatchery stock, presenting no significant differences from wild conspecifics in either fork length or body weight.     

Parentage assignment in hatchery population of brown sole <Emphasis Type="Italic">Pleuronectes herzensteini</Emphasis> by microsatellite DNA markers

ABSTRACT:   Five loci ( Phz2 , Phz6 , Phz7 , Phz12 , and Phz14 ) of microsatellite DNA markers developed in a previous study for parentage assignment in the hatchery population generated by mating among 61 broodstock fish (35 females and 26 males) in a spawning tank, were selected. After natural spawning in the same tank, larvae collected at three different times were categorized into early phase (EP), middle phase (MP), and late phase (LP) groups. In the parental broodstock, the mean number of alleles per locus was 21.8 and expected heterozygosity ( H _E ) was 0.813. In the progeny, the mean number of alleles per locus decreased to 11.6 (EP), 14.4 (MP), and 6.4 (LP) and H _E to 0.796 (EP), 0.833 (MP), and 0.681 (LP). Parental assignment determined eight dams and six sires as major parents for the EP group. In the MP group, 13 dams and ten sires genetically contributed to spawning, but only three dams and two sires were involved in LP group progeny. In the hatchery population produced from a limited number of parental fish such as the LP group, genetic variability was apparently decreased.     

Cross-species amplification of microsatellite markers for the brown sole in the family Pleuronectidae

Amplification of eight microsatellite loci previously developed and characterized in brown sole Pleuronectes herzensteini was attempted in 11 other flatfish species. Two loci, Phz6 and Phz12, were amplified in all the species examined. Cross-species amplification was successful in eight loci of Kareius bicoloratus and Pleuronectes yokohamae, but in only seven loci of Microstomus achne, Pleuronectes punctatissimus, and Pleuronectes schrenki. Three to five loci could be amplified in six other species. In the three species selected, K. bicoloratus, P. punctatissimus, and P. yokohamae, seven to eight cross-amplified loci exhibited polymorphisms comprising 1–22 alleles. Expected heterozygosity (He) ranged from 0.66 to 0.96 in K. bicoloratus, from 0.62 to 0.96 in P. punctatissimus, and from 0.43 to 0.91 in P. yokohamae. Observed heterozygosity (Ho) ranged from 0.65 to 1.00 in K. bicoloratus, from 0.55 to 0.95 in P. punctatissimus, and from 0.40 to 0.95 in P. yokohamae. The Phz2, Phz3, and Phz12 loci significantly deviated in certain or all three species from Hardy–Weinberg equilibrium. The mean values of homology to the flanking-region sequences of brown sole were 93.7% in K. bicoloratus, 91.2% in P. punctatissimus, and 93.9% in P. yokohamae. These results suggest that microsatellite markers for brown sole are applicable for genetic studies in flatfish species including at least these three species.