MHC CLASS II TYPING OF MEMBERS OF THE NUKAK INDIAN TRIBE.
Juan J. Yunis1, and Emilio Yunis1.
1Instituto de Genética, Universidad Nacional de Colombia,
Bogotá, Colombia.
The Nukak or Ka 'Kua is an Indian tribe of the Guaviare
region of Colombia between the Guaviare and Inirida rivers. Prior to 1988,
little or no contact between this indian tribe and the "civilized" world
was reported, representing an ideal model to study the genetic composition
of Amerindians. There are between 500-1000 individuals, organized in groups
of 10-30 members. To survive, hunting and gathering are their main practices,
building small camps that are used for short periods of time and moving
frequently from place to place (nomads). They are linguistically related
to the Makú tribe located in the northwest region of the Amazon
jungle and to the the Bará-Yujúp, the Né dób
in the Parana Boa-Boa region and the Up'de in the northwest section of
Brazil. 29 individuals of the Nukak tribe were analized for Red cells antigens
by standard techniques and for MHC class II genes after PCR amplification
of the DRB, DQA1, DQB1 genes. For MHC class II alleles, 20/57 informative
DRB1 alleles (35.1%) were DRB1*1402, 16/57 (28.1%) were DRB1*0411, 9/57
(15.8%) were DRB1*0404, 8/57 (14%) were DRB1*1602, 2/57 (3.5) were DRB1*0802
and 2/57 (3.5%) were DRB1*0403. For DQB1, 28/57 (49.1%) alleles were DQB1*0301,
27/57 (47.4%) were DQB1*0302 and 2/57 (3.5%) were DQB1*0402. For DQA1,
28/57 (49.1%) alleles are DQA1*0501, 27/57 (47.4%) were DQA1*0301 and 2/57
(3.5%) were DQA1*0401. Only six out of 29 individuals were typed for HLA-DPB
with frequencies for DPB1*0402 83.3 % (10/12) and the remaining two alleles
were DPB1*0301 and DPB1*1401. No genetic admixture with Caucasians was
detected based on blood group typing. The MHC class II alleles present
in these Nukak individuals are consistent with those present in other Amerindian
populations of North and South America. The Nukak and their culture are
in danger, due to rapid colonization and the presence of diseases like
Flu and Measles secondary to their contact with Caucasian. Genetic distance
dendrogram have been constructed to correlate linguistic and genetic data
from other Amerindian tribes of Colombia.