Detection of the Ongoing Sorting of Ancestrally Polymorphic SINEs Toward Fixation or Loss in Populations of Two Species of Charr During Speciation

[摘要] The Fok I family of short interspersed repetitive elements (SINEs) has been found only in the genomes of charr fishes (genus Salvelinus). In an analysis of the insertion of Fok I SINEs using PCR, we characterized six loci at which Fok I SINEs have been inserted into the genomes of Salvelinus alpinus (Arctic charr) and/or S. malma (Dolly Varden). An analysis of one locus ( Fok -223) suggested that a sister relationship exists between S. alpinus and S. malma and the SINE at this locus might have been inserted in a common ancestor of these two species, being fixed in all extant populations examined. By contrast, SINEs at two other loci ( Fok -211 and Fok -206) were present specifically in the genome of S. alpinus , with polymorphism among populations of this species. Moreover, the presence or absence of the SINEs of the other three loci ( Fok -214, Fok -217, and Fok -600) varied among populations of these two species. The most plausible interpretation of this result is that SINEs, which were ancestrally polymorphic in the genome of a common ancestor of these two species, are involved in an ongoing process of differential sorting and subsequent fixation in the various populations of each species.

[学科分类] 医学（综合）