Homoeologous crossovers are distally biased and underlie genomic instability in first-generation neo-allopolyploid Arabidopsis suecica.

Autor: Nibau C; Institute of Biological, Environmental & Rural Sciences (IBERS), Aberystwyth University, Gogerddan, Aberystwyth, Ceredigion, SY23 3EE, UK., Evans A; Institute of Biological, Environmental & Rural Sciences (IBERS), Aberystwyth University, Gogerddan, Aberystwyth, Ceredigion, SY23 3EE, UK., King H; Institute of Biological, Environmental & Rural Sciences (IBERS), Aberystwyth University, Gogerddan, Aberystwyth, Ceredigion, SY23 3EE, UK., Phillips DW; Department of Life Sciences, Aberystwyth University, Penglais, Aberystwyth, Ceredigion, SY23 3DA, UK., Lloyd A; Institute of Biological, Environmental & Rural Sciences (IBERS), Aberystwyth University, Gogerddan, Aberystwyth, Ceredigion, SY23 3EE, UK.
Jazyk: angličtina
Zdroj: The New phytologist [New Phytol] 2024 Nov; Vol. 244 (4), pp. 1315-1327. Date of Electronic Publication: 2024 Sep 06.
DOI: 10.1111/nph.20095
Abstrakt: First-generation polyploids often suffer from more meiotic errors and lower fertility than established wild polyploid populations. One such example is the allopolyploid model species Arabidopsis suecica which originated c. 16 000 generations ago. We present here a comparison of meiosis and its outcomes in naturally evolved and first-generation 'synthetic' A. suecica using a combination of cytological and genomic approaches. We show that while meiosis in natural lines is largely diploid-like, synthetic lines have high levels of meiotic errors including incomplete synapsis and nonhomologous crossover formation. Whole-genome re-sequencing of progeny revealed 20-fold higher levels of homoeologous exchange and eightfold higher aneuploidy originating from synthetic parents. Homoeologous exchanges showed a strong distal bias and occurred predominantly in genes, regularly generating novel protein variants. We also observed that homoeologous exchanges can generate megabase scale INDELs when occurring in regions of inverted synteny. Finally, we observed evidence of sex-specific differences in adaptation to polyploidy with higher success in reciprocal crosses to natural lines when synthetic plants were used as the female parent. Our results directly link cytological phenotypes in A. suecica with their genomic outcomes, demonstrating that homoeologous crossovers underlie genomic instability in neo-allopolyploids and are more distally biased than homologous crossovers.
(© 2024 The Author(s). New Phytologist © 2024 New Phytologist Foundation.)
Databáze: MEDLINE
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