Tandemly repeated satellite DNA of Dolichopoda schiavazzii: a test for models on the evolution of highly repetitive DNA.

Three specific satellite DNA families can be detected in the genome of the cave cricket Dolichopoda schiavazzii. The pDoP102 and the pDsPv400 families are species specific for D. schiavazzii; the pDoP500 family is probably present in all Dolichopoda species. The three satellite DNA families were characterized from individuals of three isolated populations of D. schiavazzii with respect to nucleotide sequence, sequence complexity, sequence variability, and copy number. This unique data set on satellite DNAs of D. schiavazzii seems to allow one to test the significance of theoretical approaches to the mode of evolution of noncoding, tandemly arranged satellite DNA. At least for satellite DNAs of D. schiavazzii two clear trends were observed: (1) sequence variability increases with copy number and (2) the repeat length decreases with copy number. The first trend is in good agreement with the theory but the second is not. Thus, a revision of the models is proposed.