engleski

An interplay of selective pressure and stochastic events direct evolution of satellite DNA library

In this work we characterized three related satellite DNA sequences coexisting in the form of a library in mitotic parthenogenetic root-knot nematodes of the genus Meloidogyne. Analysis of variability patterns among three MEL-172 satellites revealed in their monomer sequences colocalization of two domains highly reluctant to sequence changes, two domains characterized by limited number of mutations, and one showing rapid spread and homogenization of changes. Conserved distribution of intersatellite variability in the library of MEL-172 satellites might indicate a complex pattern of functional interactions. The evolution of these satellites seems to be driven by an interplay of selective constraints and stochastic events: new satellites firs diverged from an ancestral progenitor sequence by accumulating mutations in particular sequence segments, and then, the whole-length monomers of new satellites are homogenized, differentially amplified, and maintained in the form of a library.

satellite DNA; tandem repeats; concerted evolution; selective constraints

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