A Newly Isolated Family of Short Interspersed Repetitive Elements (SINEs) in Coregonid Fishes (Whitefish) With Sequences That Are Almost Identical To Those of the SmaI Family of Repeats: Possible Evidence for the Horizontal Transfer of SINEs

[摘要] The Sma I family of repeats is present only in the chum salmon and the pink salmon, and it is not present in five other species in the same genus or in other species in closely related genera. In the present study, we showed that another short interspersed repetitive elements (SINEs) family, which is almost identical to the Sma I family, is present in all fishes in the subfamily Coregoninae, being regarded as the most primitive salmonids. This new family of SINEs was designated the Sma I-cor family ( Sma I family of repeats in coregonids). The consensus sequence of the Sma I-cor family was found to be 98.6% homologous to that of the Sma I family. Accordingly, it is difficult to explain the high degree of homology between these two families of SINEs by any mechanism other than the horizontal transfer of SINEs. The estimates of the rate of neutral mutation of nuclear genes, comparing chum salmon and European whitefish, confirmed this possibility. Our results strongly suggest that a member(s) of the Sma I-cor family might have been transferred horizontally from one coregonid species to a common ancestor of chum and pink salmon or to these two species independently, to allow subsequent amplification of the Sma I family in their respective genomes.

[学科分类] 医学（综合）