Inferring the history of the polyploid Silene aegaea (Caryophyllaceae) using plastid and homoeologous nuclear DNA sequences

The origin of the rare allotetraploid Silene aegaea was inferred from plast id rps16 intron sequences, homoeologous copies of nuclear ribosomal interna l transcribed spacer (ITS) sequences, and an intron from the nuclear gene c oding for the second largest subunit of RNA polymerase II (RPB2). The nucle ar DNA regions support the S. sedoides and S. pentelica lineages as most cl osely related to the two S. aegaea paralogues. A few recombinant ITS sequen ces were found, but as PCR recombination could be demonstrated, no true rec ombination could be demonstrated. No recombination was found in the RPB2 se quences. Plastid rps16 intron sequences strongly support S. pentelica as th e maternal lineage. The strength of the approach of using homoeologous sequ ences of several loci is demonstrated, and its usefulness for the study of phylogenies of groups including polyploids is emphasized. (C) 2001 Academic Press.