AMAZON RIVER DOLPHIN POLYMORPHISM AND POPULATION DIFFERENTIATION OF MHC CLASS II PEPTIDES - Biology, Evolution and Conservation of River Dolphins Within South America and Asia - page 117

Chapter 7
A MAZON R IVER D OLPHIN P OLYMORPHISM AND
P OPULATION D IFFERENTIATION OF MHC
C LASS II P EPTIDES
María Martínez-Agüero 1 , Sergio Flores-Ramírez 2 and
Manuel Ruiz-García 1 
1 Unidad de Genética (Grupo de Genética de Poblaciones Molecular y Biología
Evolutiva). Departamento de Biología. Facultad de Ciencias. Pontificia Universidad
Javeriana, Bogotá DC, Colombia
2 Laboratorio de Ecología Molecular y Genética de la Conservación, Universidad
Autónoma de Baja California Sur, México
A BSTRACT
Inia , the Amazon River dolphin, inhabits the three major basins of northern South
America (Beni-Mamoré, Amazon and Orinoco). We analyzed class II DQB MHC gene
peptide sequences in 60 dolphins from Bolivia (Beni-Mamoré), Peru (Amazon) and
Colombia (Orinoco). Sixteen (16) peptide alleles were identified, generated by 17
polymorphic sites, most of them on the peptide binding region (PBR) residues. Four of
the alleles were the most frequent of all the populations and several private alleles for
each basin were found. A high level of polymorphism in the class II gene was
determined, similar to those reported for the Chinese river dolphins, such as the Baiji and
the finless porpoise. This polymorphism could be an adaptive response to the high level
of pathogens in freshwater.
Keywords : MHC, DQB, Inia geoffrensis, gene variability, adaptative response, Bolivia, Peru,
Colombia .
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