HLA in Jaidukama: an Amerindian secluded Colombian population with new haplotypes and Asian and Pacific-shared alleles.

America first inhabitants and peopling are still debated. In order to increase knowledge about these questions, we have aimed to detect HLA genes of an Amerindian secluded community: Jaidukama, who lives in North Colombia Equatorial forest. HLA genotyping and extended haplotype calculations were carried out in 39 healthy individuals belonging to 13 families. HLA frequencies were compared to other Amerindians and worldwide populations by calculating genetic distances, relatedness dendrograms and correspondence analyses. Only four DRB1 alleles were found (*0404, *0407, *1402 and *1602); however a total of 17 Amerindian different extended class I-class II HLA haplotypes were directly counted from the family studies, nine of them were specific of Jaidukamas. Some of the alleles or group of alleles within an extended haplotype (i.e. DQB1-DRB1) were also found in Asians and Pacific Islanders, further supporting existence of Asian and Pacific gene flow with Amerindians or a common founder effect. It is further supported that HLA extended haplotypes vary faster than alleles in populations. It is concluded that this unique model of Amerindian secluded families study suggests that rapid HLA haplotype variation may be more important than allele variation for survival (starting immune responses). This work may also be useful for future transplant programs in the area.

The Origin of Amerindians and the Peopling of the Americas According to HLA Genes: Admixture with Asian and Pacific People.

The classical three-waves theory of American peopling through Beringia was based on a mixed anthropological and linguistic methodology. The use of mtDNA, Y chromosome and other DNA markers offers different results according to the different markers and methodologies chosen by different authors. At present, the peopling of Americas remains uncertain, regarding: time of population, number of peopling waves and place of peopling entrance among other related issues. In the present review, we have gathered most available HLA data already obtained about First Native American populations, which raise some doubts about the classical three waves of American peopling hypothesis. In summary, our conclusions are: 1) North West Canadian Athabaskans have had gene flow with: a) close neighboring populations, b) Amerindians, c) Pacific Islanders including East Australians and d) Siberians; 2) Beringia was probably not the only entrance of people to America: Pacific Ocean boat trips may have contributed to the HLA genetic American profile (or the opposite could also be true); 3) Amerindians entrance to America may have been different to that of Athabaskans and Eskimos and Amerindians may have been in their lands long before Athabaskans and Eskimos because they present and altogether different set of HLA-DRB1 allele frequencies; 4) Amerindians show very few "particular alleles", almost all are shared with other Amerindians, Athabaskans and Pacific Islanders, including East Australians and Siberians; 5) Our results do not support the three waves model of American peopling, but another model where the people entrance is not only Beringia, but also Pacific Coast. Reverse migration (America to Asia) is not discarded and different movements of people in either direction in different times are supported by the Athabaskan population admixture with Asian-Pacific population and with Amerindians, 6) HLA variability is more common than allele veriability in Amerindians. Finally, it is shown that gene genealogy analises should be completed with allele frequency analyses in population relatednes and migrations studies.