engleski

The evolution of the tetraploid Anemone multifida (2n = 32) and hexaploid A. baldensis (2n = 48) (Ranunculaceae) was accompanied by rDNA loci loss and intergenomic translocation: evidence for their common genome origin

In the genus Anemone two small groups of taxa occur with the highest ploidy levels 2n = 6x = 48, belonging to the closely related clades: the montane/alpine Baldensis clade and the more temperate Multifida clade. To understand the formation of polyploids within these groups, we analyzed the evolution of allohexaploid A. baldensis (AABBDD, 2n = 6x = 48) from Europe and allotetraploid Anemone multifida (BBDD, 2n = 4x = 32) from America. ITS and NTS sequences were used as molecular markers for phylogenetic analyses Cytogenetic studies including GISH with genomic DNAs of potential parental species as probe, FISH with 5S and 18S rDNA as probes and 18S rDNA restriction analyses were used to identify the parental origin of chromosomes and to study genomic changes following polyploidization. This study shows that A. multifida (BBDD, 2n= 4x = 32) and A. baldensis (AABBDD, 2n = 6x = 48) are allopolyploids originating from the crosses of diploid members of the Multifida (donor of the A and B subgenomes) and Baldensis groups (donor of the D subgenome). The A and B subgenomes are closely related to the genomes of A. sylvestris, A. virginiana and A. cylindrica indicating that these species or their progeny might be the ancestral donors of the B subgenome of A. multifida and A and B subgenomes of A. baldensis. Both polyploids have undergone genomic changes such as interchromosomal translocation affecting B and D subgenomes and changes at rDNA sites. A. multifida has lost the 35S rDNA loci characteristic of the maternal donor (B subgenome) and maintained only the rDNA loci of the paternal donor (D subgenome). We propose that A. multifida and A. baldensis probably had a common ancestor and their evolution was facilitated by the vegetation changes during the quaternary resulting in their present disjunctive distribution.

5S rDNA intergenic spacer; Anemone; fluorescent in situ hybridization; genomic in situ hybridization; intergenomic translocation; ITS; polyploidy

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