Genetics of Zoarces populations:: X. Selection component analysis of the EstIII polymorphism using samples of successive cohorts

The eelpout population in Kald Cove has been sampled in five consecutive years, from 1969-1974. Each winter a sample including mother-offspring combinations was procured and analyzed for Est/I/ . The samples in the years 1969-1971 have been published. This paper reports on the samples in 1972, 1973 and 1974. The total data of the five year period analyzed here comprised 12,607 adults (5935 motheroffspring combinations) and 253 adolescents. The adults have been sorted into five age classes, which permits the observation of seven discrete cohorts. The data have been subjected to a refined selection component analysis, introducing analysis of the time stability of the population and the adult zygotic selection component, i.e. the viability of differences between the genotypes during their mature life. The new data support the previously found deficit of heterozygotes among adults and indicate that it arises from juvenile zygotic selection, i.e. selection occurring by differential elimination of the zygotes before maturity. The previous preliminary indications of reproductive selection have not been confirmed in this more extensive analysis.