Development and characterization of ten novel microsatellite loci for the emu (Dromaius novaehollandiae) and genetic diversity of Japanese farm populations.

The emu (Dromaius novaehollandiae) is a useful poultry animal farmed for fat, meat, and eggs. Genetic structure and relationships among farmed emu populations in Japan are unknown and the number of microsatellite markers for genetic analysis of the emu is insufficient. In this study, we isolated 16 microsatellites from the emu genome and developed ten new microsatellite markers. These microsatellite markers were used to characterize three farm emu populations in Japan. The number of alleles ranged from 3 to 13 and the expected (H) and observed heterozygosity (H) of these microsatellite loci was 0.187-0.802 and 0.179-0.647, respectively. The polymorphic information content ranged from 0.176 to 0.786. Positive inbreeding coefficient (F) values were detected in all tested populations, and they ranged from 0.027 to 0.540. These results suggest that farm populations of the emu in Japan resulted from inbreeding. The fixation index (F) values ranged from 0.026 to 0.061, and phylogenetic trees and population structure analysis confirmed no definitive genetic differentiation among the three populations. Therefore, these populations are at a relatively low level of genetic differentiation at present. The microsatellite markers developed in our study can be utilized for genetic analysis and preservation of genetic resources in the emu.