[Human genetics studies in areas of high natural radiation. VII. Genetic load].

Two methods to estimate the inbreeding load (Morton, Crow and Muller17 1956; Freire-Maia and Freire-Maia6 1965) are reviewed. Both are employed in the analysis of our data. Besides the total population, a sample constituted of individuals with no alien ancestral is also analysed. No clean effect of natural radioactivity, as measured by genetic load models, has been found (this is especially valid for abortions, pre-natal mortality, anomalies, and abnormalities in general). The results on stillbirths and post-natal and total mortalities are discussed, and it is concluded that most probably the differences found are due to uncontrolled concomitant variables (if not to chance alone). Further analysis are under way.