NEWPORT, Ore. Magellanic penguins have a high level of variation in genes associated with the ability to fight infectious disease, but a recent study found that the mechanism the penguins use to ensure that diversity is far from black and white.
Found exclusively south of the equator in South America, Magellanic penguins assemble in large nesting colonies along the coasts of Argentina, Chile, and the Falkland Islands. They typically mate for life, producing clutches of two eggs that are cared for by both parents. While individual colonies can number in the millions of birds, the species as a whole appears to be in decline, and is therefore classified as "Near Vulnerable" by the IUCN Red List.
A recent study published via Advance Access (doi: 10.1093/jhered/ess054) in the Journal of Heredity tested whether the significant diversity in the Major Histocompatibility Complex (MHC) genome region observed in these birds is attributable to mate choice or genetic selection based on disease exposure.
The study first confirmed that MHC diversity is high in these birds compared to other closely-related penguin species. Gabrielle Knafler, a graduate student at Bowling Green University and the first author of the study, explained, "By looking at the MHC genotypes of 50 breeding pairs of Magellanic penguins, we found considerable levels of genetic variation, detecting a significantly greater number of MHC variants or alleles than those reported for Galapagos penguins and Humboldt penguins." Forty-five alleles were found at the gene locus for the Magellanic penguins, sampled from a wild population in southern Patagonia, compared to 3 for Galapagos penguins and 7 for captive Humboldt penguins.
The authors of this study then investigated two possible mechanisms for maintaining the high MHC diversity in the Magellanic penguins: balancing selection, in which heterozygous individuals are better adapted to combat a wide range of dise
|Contact: Nancy Steinberg|
Journal of Heredity