ORIGIN OF AMERINDIAN Y-CHROMOSOMES AS INFERRED BY THE ANALYSIS OF 6 POLYMORPHIC MARKERS

We analysed the frequency of six Y-specific polymorphisms in 105 Ameri ndian males from seven different populations, 42 Caucasian males, and a small number of males of African, Chinese, and Melanesian origin, Th e combination of three of the six polymorphisms studied produced four different Y-haplogroups. The haplogroup A (non-variant) was the most f requent one. Eighty-five percent of Amerindians showing haplogroup A h ave the alphoid II (alpha hII) and the DYS19A Y-specific markers, an a ssociation that is found only in 10% of Caucasians and that has not be en detected in Asiatics and Africans, Haplogroups C (YAP+) and D (YAP plus an A --> G transition in the locus DYS271) are of African origin , Four percent of Amerindians and similar to 12% of Caucasians showed haplogroup C; similar to 1% of Amerindians and similar to 2% of Caucas ians had haplogroup D. Haplogroup B is characterized by a C --> T tran sition in nucleotide position 373 of the SRY gene domain; this haplogr oup is found in Caucasians (similar to 12%) and Amerindians (similar t o 4%). None of the Amerindians exhibiting the haplogroups B, C, or D s how the haplotype alpha hII/DYS19A, By haplotyping the Alu insert and the DNA region surrounding the insert in YAP+ individuals, we could de monstrate that Amerindian Y chromosomes bearing African markers (haplo groups C and D) are due to recent genetic admixture. Most non-alpha hI I/DYS19A Amerindian Y-chromosomes in haplogroup A and most cases in ha plogroup B are also due to gene flow. We show that haplotype alpha hII /DYS19A is in linkage disequilibrium with a C --> T transition in the locus DYS199, Our results suggest that most Amerindian Y-chromosomes d erive from a single paternal lineage characterized by the alpha hII/DY S19A/DYS199T Amerindian-specific haplotype, The analysis of a larger s ample of native American Y-chromosomes will be required in order to co nfirm or correct this hypothesis. (C) 1997 Wiley-Liss, Inc.