Genome Sequencing Reveals the Origin of the Allotetraploid Arabidopsis suecica.
Mol Biol Evol
; 34(4): 957-968, 2017 04 01.
Article
em En
| MEDLINE
| ID: mdl-28087777
ABSTRACT
Polyploidy is an example of instantaneous speciation when it involves the formation of a new cytotype that is incompatible with the parental species. Because new polyploid individuals are likely to be rare, establishment of a new species is unlikely unless polyploids are able to reproduce through self-fertilization (selfing), or asexually. Conversely, selfing (or asexuality) makes it possible for polyploid species to originate from a single individual-a bona fide speciation event. The extent to which this happens is not known. Here, we consider the origin of Arabidopsis suecica, a selfing allopolyploid between Arabidopsis thaliana and Arabidopsis arenosa, which has hitherto been considered to be an example of a unique origin. Based on whole-genome re-sequencing of 15 natural A. suecica accessions, we identify ubiquitous shared polymorphism with the parental species, and hence conclusively reject a unique origin in favor of multiple founding individuals. We further estimate that the species originated after the last glacial maximum in Eastern Europe or central Eurasia (rather than Sweden, as the name might suggest). Finally, annotation of the self-incompatibility loci in A. suecica revealed that both loci carry non-functional alleles. The locus inherited from the selfing A. thaliana is fixed for an ancestral non-functional allele, whereas the locus inherited from the outcrossing A. arenosa is fixed for a novel loss-of-function allele. Furthermore, the allele inherited from A. thaliana is predicted to transcriptionally silence the allele inherited from A. arenosa, suggesting that loss of self-incompatibility may have been instantaneous.
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Base de dados:
MEDLINE
Assunto principal:
Mapeamento Cromossômico
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Arabidopsis
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Especiação Genética
Idioma:
En
Revista:
Mol Biol Evol
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2017
Tipo de documento:
Article
País de afiliação:
Áustria