Data/hora: 11/06/2024 06:29:40

Provedor de dados: | Institutional Archive of Ifreme (ArchiMer)
País: | France
Título: | Mise en évidence expérimentale de la variance du succès reproducteur chez l'huître creuse Crassostrea gigas (Thunberg)
Autores: | Boudry, Pierre; Collet, Bertrand; Cornette, Florence; Hervouet, Veronique; Kotoulas, G.; Bonhomme, Francois.
Data: | 1999-09-05
Ano: | 1999
Palavras-chave: | Microsatellite; Succès reproducteur; Contributions parentales; Génétique; Crassostrea gigas; Huîtres.
Resumo: | Oysters, like many other marine species, are characterized by very high fertilities. Natural or hatchery populations, often present very low Ne/N ratios (Hedgecock, 1994). It can be explained by very high variances of their breeding success (Li and Hedgecock, 1998), the effective population size being estimated through the temporal variance of the allelic frequencies in natural populations (Hedgecock et al., 1992) or, more directly, through the estimated number of founders in hatchery populations (Launey, 1998). This document is a presentation of the results of a number of experiments, realised in the scope of the European program "GENEPHYS" (FAIR 95-421), and using microsatellite markers to analyse the parental contributions in the flat oyster Crassostrea gigas in vitro crossbreedings. The relatedness analysis was made easier by the large polymorphism (more than 50 alleles/loci) observed in the four studied loci. Thus, in a crossbreeding involving 20 males and 20 females, the father or mother of a quarter of the sibs could be determined with only one microsatellite locus. In crossbreeding involving 5 males and 5 females, each sib could be assigned to a family using 3 loci. Despite balanced parental gametic contributions at the time of fertilization, unbalanced parental contributions are observed in sibs, during larval and juvenile stages. In order to identify the causes of those imbalances, the effects of the zygotic and gametic competition have been studied, comparing different types of crossbreeding (enabling or not a gametic competition at the time of fertilization) at different stages of their development (larval and post-larval). The parental effects (male and female) on the survival of the sibs are significant. As a consequence, the variance of the individual breeding success is both due to spermatic competition phenomena and selection phenomena (differential mortality between sibs). These experimental results help us understand better the studies conducted on natural populations and open up new perspectives in terms of selection for this species of aquacultural interest.
Tipo: | Text
Idioma: | Francês
Identificador: | http://archimer.ifremer.fr/doc/1999/acte-3454.pdf
Editor: | XXIème Réunion Annuelle du Groupe de Biologie et Génétique des Populations
Relação: | http://archimer.ifremer.fr/doc/00000/3454/
Formato: | application/pdf