FAMILY NAMES AND THE LENGTH OF THE Y-CHROMOSOME IN BRAZILIAN BLACKS

The variability of the lengths of the heterochromatic and euchromatic segments of the human Y chromosome was studied by a quantitative metho d of densitometric measurement in 60 normal and unrelated black indivi duals (30 with and 30 without devotional surnames), living in Salvador , Bahia, northeastern Brazil. Thirty normal and unrelated Caucasian in dividuals of European origin, living in Curitiba, Parana, south Brazil , were included as controls. The heterochromatic segment and total Y c hromosome lengths were greater in caucasians than in blacks without de votional surnames, and these were greater than in blacks with devotion al surnames. These findings are in agreement with previous reports of a higher percentage of black ancestry in blacks carrying devotional su rnames than those carrying non-devotional ones.