GENETIC-STRUCTURE OF AUTOCHTHONOUS POPULATIONS OF MESO-AMERICA - MEXICO

We analyze the possible effect of gene flow on the genetic structure o f present-day Mexicans. For this purpose we reviewed previous admixtur e estimates for various Indian and Mestizo groups, Several facts seem clear: (1) There are no pure Indian groups in Mexico, because all Indi an groups show variable degrees of admixture, mostly with whites (rang e, 0.088 in the Huichol to 0.373 in the Huasteco); (2) the main ancest ral contribution to the noncoastal lower middle class Mestizo populati ons is Indian (above 50%) so that from a genetic standpoint Indians an d lower middle class Mestizos are not much different; and (3) black an cestry is quite high on the coasts, ranging from 0.127 to 0.405 on the east coast, and is present in other Mestizos, ranging in large urban centers from 0.027 in Oaxaca to 0.107 in Puebla and in smaller cities from 0.08 in Tlaxcala to 0.181 in Cuanalan.