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.
OBJECTIVE
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, the evolution of allohexaploid A. baldensis (AABBDD, 2n = 6x = 48) from Europe and allotetraploid Anemone multifida (BBDD, 2n = 4x = 32) from America was analysed.


METHODS
Internal transcribed spacer and non-transcribed spacer sequences were used as molecular markers for phylogenetic analyses. Cytogenetic studies, including genomic in situ hybridization with genomic DNA of potential parental species as probe, fluorescence in situ hybridization 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.


RESULTS
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. Anemone 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).


CONCLUSIONS
It is proposed that A. multifida and A. baldensis probably had a common ancestor and their evolution was facilitated by vegetation changes during the Quaternary, resulting in their present disjunctive distribution.
Faculty of Science, University of Zagreb, Division of Biology, Department of Molecular Biology, Horvatovac 102a, HR-10000 Zagreb, Croatia.
J
J
Mlinarec
Z
Z
Šatović
N
N
Malenica
I
I
Ivančić-Baće
V
V
Besendorfer
D000569:Americas; D031883:Anemone / Q000235:genetics*; D021901:DNA, Intergenic / Q000235:genetics*; D004275:DNA, Ribosomal / Q000235:genetics*; D005060:Europe; D019143:Evolution, Molecular; D005819:Genetic Markers; D014644:Genetic Variation; D010802:Phylogeny; D057891:Tetraploidy; D014178:Translocation, Genetic
D021901:DNA, Intergenic; D004275:DNA, Ribosomal; D005819:Genetic Markers