to the Americas and consequently altered the demographics.[81] Following World War II and subsequent worldwide migrations, the current American populations' genetic admixture can be traced to all corners of the world.[5][82]Blood groups[edit]Frequency of O group in indigenous populations. Note the predominance of this group in Indigenous Americans.Further information: ABO blood group systemPrior to the 1952 confirmation of DNA as the hereditary material by Alfred Hershey and Martha Chase, scientists usedblood proteins to study human genetic variation.[83][84] The ABO blood group system is widely credited to have been discovered by the Austrian Karl Landsteiner, who found three different blood types in 1900.[85] Blood groups are inherited from both parents. The ABO blood type is controlled by a single gene (the ABO gene) with three alleles: i,IA, and IB.[86]Research by Ludwik and Hanka Herschfeld during World War I found that the frequencies of blood groups A,B and O differed greatly from region to region.[84] The "O" blood type (usually resulting from the absence of both A and B alleles) is very common around the world, with a rate of 63% in all human populations.[87] Type "O" is the primary blood type among the indigenous populations of the Americas, in-particular within Central and South America populations, with a frequency of nearly 100%.[87] In indigenous North American populations the frequency of type "A" ranges from 16% to 82%.[87] This suggests again that the initial Amerindians evolved from an isolated population with a minimal number of individuals.[88][89]Distribution of ABO blood typesin various modern Indigenous Amerindian populationsTest results as of 2008[90]PEOPLE GROUPO (%)A (%)B (%)AB (%)Blackfoot (N. Am. Indian)178201Bororo (Brazil)100000Eskimos (Alaska)3844135Inuit (Eastern Canada & Greenland)5436238Hawaiians376121Indigenous North Americans (as a whole Native Nations/First Nations)791641Maya (modern)98111Navajo732700Peru100000 Genealogical testing[edit]Main article: Genealogical DNA testA genealogical DNA test examines the nucleotides at specific locations on a person's DNA for genetic genealogy purposes.[91] The test results are not meant to have any medical value; they are intended only to give genealogical information. Genealogical DNA tests generally involve comparing the results of living individuals to historic populations.[91] The general procedure for taking a genealogical DNA test involves taking a painless cheek-scraping (also known as a buccal swab) at home and mailing the sample to a genetic genealogy laboratory for testing. Genetic testing results showing specific sub-Haplogroups of Q, R1 and C3b implies that the individuals ancestry is, in whole or in-part, indigenous to the Americas.[92] If one's mtDNA belonged to specific sub-Haplogroups of, A, B, C, D or X2a, the implication would be that the individual's ancestry is, in whole or part, indigenous to the Americas.[93]See also[edit]Archaeology of the AmericasArchaeogeneticsAncient DNAClovis CultureEarly human migrationsHaplogroups of historical and famous figuresRace and geneticsY-chromosome haplogroups by populationsArchaeogenetics of the Near EastGenetics and archaeogenetics of South AsiaGenetic history of AfricaGenetic history of EuropeGenetic history of ItalyGenetic history of North AfricaGenetic history of the British IslesGenetic history of the Iberian PeninsulaIndigenous peoples of the Americas portalMolecular Anthropology portalEvolutionary biology portalIndigenous peoples of North America portalAboriginal peoples in Canada portal. Postado por ANTONIO FLORENTINO as 12/02/2012 12:21:00 PM