Mitochondrial DNA origin of indigenous Malagasy chicken: implication for a functional polymorphism at the Mx gene

Razafindraibe, H.; Mobegi, V.A.; Ommeh, S.C.; Ralptondravao, Bjørnstad, G.; Hanotte, O.; Jianlin, H. 2008. Mitochondrial DNA origin of indigenous Malagasy chickens: implication for a functional polymorphism of the Mx gene. The Annals of the New York Academy of Sciences 1149(1):77-79.

We report the mitochondrial DNA (mtDNA) characterization of 77 indigenous chickens (fighting and meat birds) from Madagascar, using DNA sequences of the first hypervariable segment of the D-loop. Comparison with reference samples from the African continent and Asia revealed two mtDNA haplogroups, suggesting a dual geographic and genetic origin for the indigenous Malagasy chickens. The most common haplogroup was present in 65 individuals of the two types; it is likely of Indonesian origin. The second haplogroup was observed in 12 fighting birds and meat chickens; it could be of African continental origin and/or the result of recent introgression with commercial lines. We further studied a G/A single nucleotide polymorphism at nucleotide position 1892 bp of the coding sequence of the Mx gene that is reported to be one of the candidate susceptible/resistant genes to viral infection in chicken. Our results indicate the "susceptible" allele G is the most common with frequencies of 65% and 70% in Malagasy fighting and meat chickens, respectively. However, the allelic frequency difference between the two types of chickens is not significant (P > 0.05). These results are discussed in light of our current linguistic and archaeological knowledge on the origin of indigenous Malagasy chickens.