Organellar inheritance in liverworts: an example of Pellia borealis.

Liverwort Pellia borealis is an allopolyploid species that originated after the hybridization and chromosome doubling of two cryptic species; Pellia epiphylla species N and Pellia epiphylla species S. A sequence comparison of chloroplast tRNAUCCGly, tRNAUUULys gene introns, the mitochondrial tRNAGCUSer gene intron, and the first intron of the coxIII gene in the case of three liverwort species studied revealed that the chloroplast and mitochondrial sequences are identical in P. borealis and P. epiphylla species N but different from homologous P. epiphylla species S sequences. Both mitochondria and chloroplasts of P. borealis were thus inherited from one parent- P. epiphylla species N. Studies on 14 different populations of P. borealis gave the same result. These are the first data on organellar transmission in liverworts, the earliest land plants. Moreover, we show that the intron sequences of some organellar genes, until now not used in any systematic studies, could be very good markers in studying taxonomic relationships in closely related species and reconstructing historical events.