Multiple Maternal Lineages of Vietnamese Local Chickens Inferred by Mitochondrial DNA D-loop Sequences

Abstract

Mitochondrial DNA (mtDNA) is considered a powerful source of molecular information to track the ancestry of breeds back hundreds of generations (Harpending et al., 1998). Different hypotheses about chicken domestication based on mtDNA analyses are found in the literature. Fumihito et al. (1996) suggested a monophyletic origin of domestic chickens from Gallus gallus gallus and that a single domestication event occurred in Thailand and adjacent regions, while Kanginakudru et al. (2008) found evidence for domestication of Indian chickens from Gallus gallus spadiceus and Gallus gallus gallus as well as from Gallus gallus murghi. A study that analyzed BCDO2, a gene encoding an enzyme which converts carotene into its colourless variant, suggested the introgression of the yellow skin gene from Gallus sonneratii into modern chicken breeds (Eriksson et al., 2008). Other reports assumed multiple and independent domestication events in South China, Southeast Asia and the Indian subcontinent (Liu et al., 2006 a; Oka et al., 2007). Liu et al. (2006) revealed nine divergent clades (named clades A-I) related to geographical distribution in a wide range of domestic chickens in Eurasian regions. Oka et al. (2007) identified seven clades (named clades A-G) in Japanese chickens of which the four clades A, B, C and E are identical to clades E, A, D and B, respectively, described by Liu et al. (2006).