Recent hybrid speciation in Cardamine (Brassicaceae) - conversion of nuclear ribosomal ITS sequences in statu nascendi

The very recent allopolyploid speciation of Cardamine insueta and Cardamine schulzii is well documented. We used this system for a further understandi ng of the evolution of the internal transcribed spacers (ITS) of nuclear ri bosomal DNA in recently formed hybrids. The ITS sequencing of the two paren t species and the alloploid offspring suggests a synopsis of the types of I TS evolution, reported so far in the literature. We detected homogenization to one parental ITS type with a very strong bias to the maternal sequence. Nevertheless, maintainance of both parental ITS sequences in the alloploid s was also recorded. Our data suggest. (1) rapid genomic change in newly fo rmed alloploids, and (2) a multiple origin of C. insueta and C. schulzii.