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Young Alu insertions within the MHC class I region in native American populations: Insights into the origin of the MHC‐ Alu repeats
Author(s) -
GómezPérez Luis,
AlfonsoSánchez Miguel A.,
Dipierri José E.,
Sánchez Dora,
Espinosa Ibone,
Pancorbo Marian M.,
Peña José A.
Publication year - 2013
Publication title -
american journal of human biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.559
H-Index - 81
eISSN - 1520-6300
pISSN - 1042-0533
DOI - 10.1002/ajhb.22377
Subject(s) - biology , major histocompatibility complex , haplotype , evolutionary biology , population , alu element , genetics , genetic diversity , allele , gene , demography , human genome , genome , sociology
Objectives Genetic heterogeneity of two Amerindian populations (Jujuy province, Argentina, and Waorani tribe, Ecuador) was characterized by analyzing data on polymorphic Alu insertions within the human major histocompatibility complex (MHC) class I region (6p21.31), which are completely nonexistent in Native Americans. We further evaluated the haplotype distribution and genetic diversity among continental ancestry groups and their potential implications for the dating of the origin of MHC‐ Alus . Methods Five MHC‐ Alu elements ( Alu MicB, Alu TF, Alu HJ, Alu HG, and Alu HF) were typed in samples from Jujuy ( N = 108) and Waorani ( N = 36). Allele and haplotype frequency data on worldwide populations were compiled to explore spatial structuring of the MHC‐ Alu diversity through AMOVA tests. We utilized the median‐joining network approach to illustrate the continental distribution of the MHC‐ Alu haplotypes and their phylogenetic relationships. Results Allele and haplotype distributions differed significantly between Jujuy and Waorani. The Waorani featured a low average heterozygosity attributable to strong population isolation. Overall, Alu markers showed great genetic heterogeneity both within and among populations. The haplotype distribution was distinctive of each continental ancestry group. Contrary to expectations, Africans showed the lowest MHC‐ Alu diversity. Conclusions Genetic drift mainly associated to population bottlenecks seems to be reflected in the low MHC‐ Alu diversity of the Amerindians, mainly in Waorani. Geographical structuring of the haplotype distribution supports the efficiency of the MHC‐ Alu loci as lineage (ancestry) markers. The markedly low Alu diversity of African populations relative to other continental clusters suggests that these MHC‐ Alu s might have arisen after the anatomically modern humans expanded out of Africa. Am. J. Hum. Biol. 25:359–365, 2013. © 2013 Wiley Periodicals, Inc.