J. Palma et al., Developmental stability and genetic heterozygosity in wild and cultured stocks of gilthead sea bream (Sparus aurata), J MARINE BI, 81(2), 2001, pp. 283-288
Citations number
23
Categorie Soggetti
Aquatic Sciences
Journal title
JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM
The present study checks on the validity of the hypothesis that heterozygos
ity and the fluctuating asymmetry, FA), common measure of the developmental
stability, are linked in populations of wild and cultured stocks of Sparus
aurata from five countries. Muscle and liver samples were analysed for var
iation in 26 allozymes and three microsatellite loci. Pectoral fin rays and
upper and lower gill rakers of the first branchial arch were counted on th
e left and on the right sides of each fish. Fluctuating asymmetry existed i
n the majority of the samples although their values were consistently low,
(0.305 +/- 0.147), but higher in the cultured samples. The allozyme heteroz
ygosity values were al-ways high, but lower in the cultured samples. The mi
crosatellite DNA analysis pro d similar results. Heterozygosity was higher
in cultured individual,; (except for the Greek samples), These findings, se
em to be early evidence that the reared samples are losing sonic genetic va
riation, especially, due to the loss of the rarest alleles (which were pres
ent in the wild populations). Genetic drift, probably caused by propagation
practices, is most likely responsible for the decrease of (lie genetic var
iation. No distinct pattern of geographic separation wa identified.