Population variation in the A chromosome distribution of satellite DNA and ribosomal DNA in the grasshopper Eyprepocnemis plorans.

The double FISH analysis of two repetitive DNAs (a satellite DNA and ribosomal DNA) in 12 natural populations of the grasshopper Eyprepocnemis plorans collected at the south (Granada and Málaga provinces) and south-east (Albacete and Murcia provinces) of the Iberian Peninsula has shown their wide-spread presence throughout the whole genome as well as extensive variation among populations. Both DNAs are found in most A chromosomes. Regularly, both DNAs occurred in the S11 and X chromosomes, rDNA in the S10 and satDNA in the L2 and M3. No correlation was found between the number of satDNA and rDNA clusters in the A genomes of the 12 populations analysed, and both figures were independent of the presence of B chromosomes. The genomic distribution of both DNAs showed no association with the geographical localization of the populations analysed. Finally, we provide evidence that the supernumerary chromosome segment proximally located on the S11 chromosome is, in most cases, the result of satDNA amplification but, in some cases, it might also derive from amplification of both satDNA and rDNA.