Organellar inheritance in the allopolyploid moss Plagiomnium curvatulum

Previous studies using isozymes have established that the moss Plagiomnium curvatulum is an allopolyploid species that originated from hybridization and chromosome doubling of Plagiomnium elatum and Plagiomnium ellipticum . It has so far remained unknown which species is the donor of chloroplasts and mitochondria to P. curvatulum . Studies of organellar inheritance in bryophytes suggest that uniparental transmission was involved. Comparison of nucleotide sequence data of three chloroplast and three mitochondrial DNA markers from P. curvatulum and its parental species reveal that the chloroplast and mitochondrial sequences of P. curvatulum and P. ellipticum are identical and differ from homologous sequences of P. elatum . Seven samples from five different populations of P. curvatulum all gave the same result. Both mitochondria and chloroplasts of P. curvatulum were inherited from P. ellipticum . The nucleotide substitution rate calculated for homologous organellar nucleotide sequences is 4.57 times higher in chloroplasts than in mitochondria. Moreover, substitution rates differ considerably between chloroplast and mitochondrial homologous intron sequences when allopolyploid species and their parental haploids from different genera of bryophytes are compared.