Rates of recombination in the ribosomal DNA of apomictically propagated Daphnia obtusa lines.

ABSTRACT: Ribosomal (r)DNA undergoes concerted evolution, the mechanisms of which are unequal crossing over and gene conversion. Despite the fundamental importance of these mechanisms to the evolution of rDNA, their rates have been estimated only in a few model species. We estimated recombination rate in rDNA by quantifying the relative frequency of intraindividual length variants in an expansion segment of the 18S rRNA gene of the cladoceran crustacean, Daphnia obtusa, in four apomictically propagated lines. We also used quantitative PCR to estimate rDNA copy number. The apomictic lines were sampled every 5 generations for 90 generations, and we considered each significant change in the frequency distribution of length variants between time intervals to be the result of a recombination event. Using

SUBMITTER: McTaggart SJ 

PROVIDER: S-EPMC1775004 | biostudies-literature | 2007 Jan

REPOSITORIES: biostudies-literature