Cegan, R., Marais, G.A.B., Kubekova, H., Blavet, N., Widmer, A., Vyskot, B., Doležel, J., Šafář, J., Hobza, R.
BMC PLANT BIOLOGY
10:
180,
2010
Klíčová slova:
Abstrakt:
Background: The evolution of sex chromosomes is often accompanied by gene or chromosome rearrangements.
Recently, the gene AP3 was characterized in the dioecious plant species Silene latifolia. It was suggested that this
gene had been transferred from an autosome to the Y chromosome.
Results: In the present study we provide evidence for the existence of an X linked copy of the AP3 gene. We
further show that the Y copy is probably located in a chromosomal region where recombination restriction
occurred during the first steps of sex chromosome evolution. A comparison of X and Y copies did not reveal any
clear signs of degenerative processes in exon regions. Instead, both X and Y copies show evidence for relaxed
selection compared to the autosomal orthologues in S. vulgaris and S. conica. We further found that promoter
sequences differ significantly. Comparison of the genic region of AP3 between the X and Y alleles and the
corresponding autosomal copies in the gynodioecious species S. vulgaris revealed a massive accumulation of
retrotransposons within one intron of the Y copy of AP3. Analysis of the genomic distribution of these repetitive
elements does not indicate that these elements played an important role in the size increase characteristic of the Y
chromosome. However, in silico expression analysis shows biased expression of individual domains of the identified
retroelements in male plants.
Conclusions: We characterized the structure and evolution of AP3, a sex linked gene with copies on the X and Y
chromosomes in the dioecious plant S. latifolia. These copies showed complementary expression patterns and
relaxed evolution at protein level compared to autosomal orthologues, which suggests subfunctionalization. One
intron of the Y-linked allele was invaded by retrotransposons that display sex-specific expression patterns that are
similar to the expression pattern of the corresponding allele, which suggests that these transposable elements may
have influenced evolution of expression patterns of the Y copy. These data could help researchers decipher the
role of transposable elements in degenerative processes during sex chromosome evolution.
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Autoři z ÚEB: Jaroslav Doležel,
Jan Šafář
Čeština
English