Evidence of pre-introduction hybridization of Formosan sika deer (Cervus nippon taiouanus) on Okinoshima, Wakayama Prefecture, Japan, based on mitochondrial and nuclear DNA sequences

Abstract

To examine the origin of the Formosan sika deer (Cervus nippon taiouanus) introduced to the island of Okinoshima (Wakayama Prefecture, Japan), sixteen tissue samples from Okinoshima population were analyzed to determine sequence variation in maternal mitochondrial DNA (mtDNA) cytochrome b and nuclear DNA α-lactalbumin (αLAlb). Three cytochrome b haplotypes were found in the Okinoshima population, two Formosan sika deer haplotypes and one Formosan sambar (C. unicolor swinhoei) haplotype. Three nuclear DNA αLAlb sequences, i.e. Formosan sika deer, red deer (C. elaphus), and additional one unknown sequence were detected in the population. Cytonuclear disequilibrium was observed in five individuals, indicating that the Okinoshima population have occurrence of hybrid among the three deer species. The deer introduced on Okinoshima might have originated from a private deer-breeding facility in Taiwan. To avoid native Japanese sika deer (e.g. C. n. centralis) genetic introgression, the Okinoshima population should be isolated from native Japanese sika deer populations.