title: New DNA markers for discrimination between closely-related species and for the reconstruction of historical events; an example using liverworts.
abstract: A survey of fully-sequenced chloroplast genomes revealed that in land plants there are six tRNA genes that have introns. Moreover, the length of a particular tRNA gene intron remains relatively stable across species. However, in algae, the presence of chloroplast tRNA genes containing introns is exceptional. A survey of mitochondrial plant genomes revealed intron-containing tRNA genes are rather rare features, with the exception of tRNASerGCU genes in liverworts and peat-mosses. We isolated and sequenced one mitochondrial and three chloroplast intron-containing tRNA genes and a fragment of the mitochondrial coxIII gene containing the first intron from the following liverwort species: Pellia borealis, Pellia epiphylla-species N, Pellia epiphylla-species S and Porella baueri, Porella cordaeana, Porella platyphylla. We showed that, as in the case of higher plants, the rate of nucleotide substitution is lower in the mitochondrial genome than in the chloroplast genome. Moreover, the comparison of intron nucleotide sequences enabled us to show that in the case of one allopolyploid species, Pellia borealis, organelles were transmitted from one parent species, Pellia epiphylla-species N. In the case of another allopolyploid species, Porella baueri, organelles were also inherited from one parent species, Porella cordaeana. Therefore, organellar inheritance in liverworts seems to be uniparental. It remains clear that analysis of carefully chosen chloroplast and mitochondrial DNA sequences allowed us to reconstruct historical events.
authors.affiliation: Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Miedzychodzka 5, 60-371 Poznań, Poland. zofszwey@main.amu.edu.pl
authors.forename: Zofia
authors.initials: Z
authors.lastname: Szweykowska-Kulińska
authors.forename: Andrzej
authors.initials: A
authors.lastname: Pacak
authors.forename: Kamila
authors.initials: K
authors.lastname: Jankowiak
mesh_terms: D018742:DNA, Chloroplast / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics; D019143:Evolution, Molecular; D005111:Extrachromosomal Inheritance; D017343:Genes, Plant; D005819:Genetic Markers; D035926:Hepatophyta / Q000145:classification / Q000235:genetics*; D007438:Introns / Q000235:genetics; D011003:Ploidies; D016133:Polymerase Chain Reaction; D012343:RNA, Transfer / Q000235:genetics; D013045:Species Specificity
chemical_list: D018742:DNA, Chloroplast; D004272:DNA, Mitochondrial; D005819:Genetic Markers; D012343:RNA, Transfer