The relationship of the Mayas to other indigenous peoples of the Americas has been assessed using traditional genetic markers. Mayas inhabited several parts of Mexico and Central America, including Chiapas, the northern lowlands of the Yucatán Peninsula, the southern lowlands and highlands of Guatemala, Belize, and parts of western El Salvador and Honduras. Genetic studies of the Maya people are reported to show higher levels of variation when compared to other groups. Maya intra-population variation has been examined by means of the following tests: Human leukocyte antigen (HLA) polymorphisms, polymorphic Alu insertions, mitochondrial DNA (mtDNA), and Y chromosome data. The results indicate that ancestors of the Mayas made a finite number of entries into the Americas over the Bering land bridge.
Human leukocyte antigen polymorphisms In a study conducted by Michael H. Crawford, human leukocyte antigen loci were found to encode for major histocompatibility complexes. Allele frequencies were plotted for similarities using principal component analysis (PCA) for the HLA-A locus exhibited by the Mayan population. Results plot close similarities with the Inupiat people of Native Alaskan heritage, the Waiapi of central Brazil and the Tohono O'odham of northern Mexico. The HLA-B locus was examined in a PCA plot and indicates a proximity to the Zuni of southwest North America and the Aymara of southern South America.
Transferrins, immunoglobulins and globulin allotypes In a study conducted by Crawford, the transferrin, TF*B, allele was found to occur among the Lacandon Maya at a frequency of .019, among a group of mestizos (admixture of indigenous and Spanish people) of Tlaxcala (0.23), the Pima of the southwestern U.S. (0.32), the Chinantecos (0.28), and the Cora (0.05). Crawford states “The chance occurrence of the same mutation was acted upon by either the founder effect or selection”. The GM immunoglobulin allotype is inherited from both parents in units called haplotypes and carried amongst populations. The GM system diagnosis reveals population similarities and levels of admixture. Among the Maya population, the haplotypes present are: GM*A G (64.9), GM*X G (12.3) and GM*A T (4.4). GM frequencies of distinct Siberian groups has been documented. The Samoyeds and the Na-Dene express high frequencies of GM*X G and GM*A T. The Eskimo and Chukchi people display high frequencies of GM*A G and intermediate frequencies of GM*A T.
Mitochondrial DNA (mtDNA)
mtDNA frequency distributions throughout the Americas A study by Herrera et al. detailed genetic affinities between four groups of Maya: Mayas of Buctzotz and Yucatán, Kaqchikel people, Mayas of Campeche, and the K'iche' people. "Intra-population diversity was presented as four (APO, COL3A1, NBC4 and TCR) of the ten loci displayed allelic frequencies at fixation for the insertion or lack of insertion state". Three (APO, NBC4 and PV92) represent fixation of the insertion allele, while it was absent in non-native groups . Heterozygosity averages among the ten loci from the K'iche' at 0.133, the Buctzotz group at 0.249 and the Kaqchikel 0.171. Inter-population diversity was reported in reference to differences in allelic frequencies between the Mayans and other Native Americans, Europeans, Africans and Asians as (P<0.001).
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