MULTIPLE FOUNDER HAPLOTYPES OF MITOCHONDRIAL-DNA IN AMERINDIANS REVEALED BY RFLP AND SEQUENCING

The mitochondrial DNA (mtDNA) of 139 individuals from eight tribes whi ch belong to four linguistic groups of the Brazilian Amazon Region was studied both by RFLP and by sequencing of the D-loop region. RFLP ana lysis showed that 41 haplotypes (29%) belonged to haplogroup A, 39 (28 %) to haplogroup B, 38 (27%) to haplogroup C, 19 (14%) to haplogroup D , and 2 (< 2%) could not be assigned to any of the four haplogroups. A mong the 92 individuals analyzed by direct sequencing of the D-loop re gion, we observed 43 different haplotypes defined by 48 polymorphic po ints, while one haplotype could not be assigned to any of the clusters previously described. Joint analysis of data obtained by RFLP and by sequencing of mtDNA demonstrated that, regardless of the method of ana lysis, the mtDNA haplotypes of contemporary Amerindians cluster into f our groups, similar to those previously described: even though 7% of t he total sample or 12% of the haplotypes have discrepancies between re sults obtained by RFLP and sequencing. In addition to supporting the p revalence of four major haplogroups among contemporary Amerindians, ou r data are compatible with multiple founder haplotypes in each haplogr oup, based on: i) a high prevalence of unusual haplotypes; ii) presenc e of multiple polymorphic sites shared by different haplogroups; iii) relative differences in nucleotide diversity based on RFLP or sequenci ng within the different haplogroups.