Naslov
Two-stage model of evolution of satellite DNA sequences: an interplay of selective constraints and stochastic events

Autori
Meštrović, Nevenka ; Castagnone-Sereno, Philippe ; Plohl, Miroslav

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, neobjavljeni rad, znanstveni

Izvornik
Genome Evolution in Eukaryotes (GEE), Bertinoro, Italia, 2006. / - , 2006

Skup
Genome Evolution in Eukaryotes (GEE)

Mjesto i datum
Bertinoro, Italija, 17.09.2006. - 22.09.2006

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
satellite DNA; concerted evolution; library hypothesis

Sažetak
According to the library model, related species have in common satellite DNA sequences amplified in differing abundances: species-specificity of satellite profiles results primarily from rapid fluctuations in the monomer copy-number while nucleotide sequences of satellite DNAs can remain unchanged for significant evolutionary periods. However, nonuniform distribution of polymorphic sites observed in many satellites suggests that some parts of satellite monomers accumulate mutations more rapidly than others, possibly as a consequence of constraints imposed on particular sequence segments. Our recent results on analysis of related satellites coexisting in the library of parthenogenetic root-knot nematodes, disclosed three different levels of variability along the monomer sequences that modulated accumulation of sequence divergences during formation of extant satellites. These observations indicate a possible paradox in the evolution of satellite sequences, since some satellites distributed in species separated over long-time periods do not show any species-specific traits even in polymorphic segments of their monomers. Based on our recent results both on sexually and asexually reproducing species we propose a two-stage model in the evolution of at least some satellite sequences. In the first stage, the necessity to meet functional requirements might determine formation of diverged satellite variants, their spread and survival in the library. In the second stage, homogenization mechanisms acting on whole-length monomers of new satellites can favor persistence of an established mutational profile along the entire monomer sequence (i.e. both in "conserved" and "variable" sequence segments). In the same time, stochastic events can be dominant in differential amplification of satellite DNAs of similar properties in the library. It can be suggested that evolution of these satellites is in both stages driven by a complex interplay of selective constraints and stochastic events.

Izvorni jezik
Engleski

Znanstvena područja
Biologija

POVEZANOST RADA