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Genetic variation of the FMR1 gene among four Mexican populations: Mestizo, Huichol, Purepecha, and Tarahumara
Author(s) -
BarrosNúñez Patricio,
RosalesReynoso Mónica Alejandra,
Sandoval Lucila,
RomeroEspinoza Pavel,
TroyoSanromán Rogelio,
Ibarra Bertha
Publication year - 2008
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.20705
Subject(s) - genetics , fmr1 , allele , biology , hum , population , allele frequency , gene , demography , history , sociology , performance art , art history
Fragile X syndrome is the most common cause of inherited mental retardation; it is caused by expansion of CGG repeats in the first exon of the FMR1 gene. The number of CGG repeats varies between 6 and 50 triplets in normal individuals; the most common alleles have 29 or 30 repeats. Allelic patterns in the global populations are similar; however; some reports show statistical differences among several populations. In Mexico, except by a single report on a western Mestizo population, the allelic frequencies of the FMR1 gene are unknown. In this study, we analyze 207, 140, 138, and 40 chromosomes from Mestizos, Tarahumaras, Huichols, and Purepechas respectively. After PCR amplification on DNA modified by sodium bisulfite treatment, molecular analysis of the FMR1 gene showed 30 different alleles among the 525 chromosomes evaluated. Trinucleotide repeat number in the different Mexican populations varied from 15 to 87, with modal numbers of 32 and 30 in Mestizos and Tarahumaras, 29 and 32 in Purepechas and 30 among Huichols. Together, these allelic patterns differ significantly from those reported for Caucasian, Chinese, African, Indonesian, Brazilian, and Chilean populations. The increased number of the unusual allele of 32 repeats observed in the Mexican mestizo population can be explained from its frequency in at least two Mexican native populations. Am. J. Hum. Biol., 2008. © 2008 Wiley‐Liss, Inc.