Molecular characterization of repetitive DNA sequences from a B chromosome

Abstract
In the parasitic waspNasonia vitripennis, certain males carry a B chromosome, called PSR (paternal sex ratio), which causes the compaction and subsequent loss of the paternal chromosomes in fertilized eggs. BecauseNasonia are haplo-diploid, this leads to the production of all-male broods. Three families (PSR2, PSR18, PSR22) of related, tandemly repetitive DNAs were shown to be present solely on the PSR chromosome. These three families shared two conserved, palindromic ANA sequences, which may play a role in either PSR function or amplification of the tandem arrays. The tandem repeat family NV79 was determined to be present on the PSR chromosome as well as on at least one of the A chromosomes. This shared repeat as well as two repeat families (NV85, NV126) that were localized on the A chromosomes were detected in two sibling species ofN. vitripennis. NV79 and NV126 were also found in the more distantly related species,Trichomalopsis dubius.