engleski

Intricate patterns of sequence divergence and conservation in an organizationally complex Donax trunculus satellite DNA family

Characterization of a novel satellite DNA family from the bivalve mollusc Donax trunculus revealed extensive grouping of monomer sequence variants and formation of subfamilies identified by distinctive combinations of diagnostic nucleotides. In addition to the tandemly organized 169 bp long monomers, at least one subfamily was created through amplification of two adjacent repeats in a higher order register, while sequence rearrangements led to the creation of a complex satellite unit. Irrespective of the differences that exist between the constituent subunits, higher order repeats can also be further divided into variant subgroups. The localization pattern of diagnostic changes indicates that sequence homogenization mechanisms are not only effective in the spread of the higher order repeat as a whole, but also act on a lower scale. Nucleotide diversity analysis of all variants of the entire satellite family revealed the persistence of conserved sequence segments which stands in contrast to the sequence and organizational divergence of various groups, and may indicate functional constraints on the evolution of this satellite.

bivalve molluscs; nucleotide diversity; homogenization; satellite subfamily

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