Genomic analysis of endogenous retrovirus elements in chinese flocks of economic importance

Since the status of endogenous retrovirus elements in Chinese chickens is currently unknown, the embryonated eggs were analyzed from 10 different chicken breeds throughout China. In this study, endogenous retrovirus elements were analyzed including: EAV, ev, ev/J, and ART-CH in the embryos of economically important chicken flocks in China. These results indicated that compared with the E51 and EAV-0, the EAV genomic sequence in the tested chicken breeds was more closely related to EAV-0. The ART-CH elements in Chinese chickens were not significantly different from the prototype ART-CH clones, 5 and 14. Although the nucleotide acid sequences of ev and ev/J in the tested chicken breeds was similar to other known ev and ev/J sequences, they belonged to different branches in the phylogenetic tree (except for Lohmann Brown layers and White Leghorns). In addition, the intact ev/J sequences indicated that these chickens were somewhat different from each other. The results reported here demonstrate that endogenous ALVs are widely distributed throughout a number of Chinese chicken breeds. The endogenous viral genomes present in the Chinese chicken breeds are genetically distinct from other endogenous viruses circulating within chicken populations.