REPRODUCTIVE-BEHAVIOR AND NATURAL-SELECTION FOR THE SICKLE GENE IN THE BAIGA TRIBE OF CENTRAL INDIA - THE ROLE OF SOCIAL PARENTING

We have investigated the transmission of the sickle cell gene in relat ion to tribal structure, and genetic fitness in a primitive Indian tri bal population, the Baiga. Factors operating on gene frequency include protection of AS individuals against falciparum malaria, a high frequ ency of genetic factors capable of moderating the severity of sickle c ell anaemia (alpha-thalassaemia and Xmn I polymorphism in G gamma gene ), a high frequency of consanguineous marriage, and reproductive compe nsation by couples at risk for sickle cell anaemia. The study incident ally made it possible to measure the extent of 'social parenting' in s uch a tribal society for the first time: deviation from expectation in the distribution of the Hb A and S genes within families suggests tha t up to 30 % of children may not be offspring of their ostensible pare nts.