INBREEDING INCIDENCE ON BIOLOGICAL FITNESS IN AN ISOLATED MEDITERRANEAN POPULATION - LA-ALTA-ALPUJARRA-ORIENTAL (SOUTHEASTERN SPAIN)

The incidence of parental inbreeding on biological fitness was analyse d in a sample of the Alpujarrenian population. Fitness was estimated a s the fertility and offspring viability from conception to reproductiv e age. The analysed sample represents about 45% of the population from the Alta Alpujarra Oriental in southeastern Spain, and includes 847 f amilies and 2916 pregnancies. The results showed slightly higher repro duction in consanguineous marriages, but the differences observed were not statistically significant. Higher pregnancy numbers are usually i nterpreted as stemming from greater immunological compatibility of the mother and foetus and may also reflect the significantly higher early foetal viability in this population. According to other authors, the great number of births observed in Alpujarrenian consanguineous marria ges is, in part, a reproductive compensation for increased perinatal a nd neonatal mortality found as a possible negative result of homozygou s combinations of deleterious alleles.