The evolutionary consequences of transposon-related pericentromer expansion in melon
Morata, Jordi (Centre de Recerca en Agrigenòmica)
Tormo, Marc (Centre de Recerca en Agrigenòmica)
Alexiou, Konstantinos G. (Institut de Recerca i Tecnologia Agroalimentàries)
Vives, Cristina (Centre de Recerca en Agrigenòmica)
Ramos-Onsins, Sebastian (Centre de Recerca en Agrigenòmica)
Garcia-Mas, Jordi (Centre de Recerca en Agrigenòmica)
Casacuberta i Suñer, Josep M. 1962- (Centre de Recerca en Agrigenòmica)

Date:	2018
Abstract:	Transposable elements (TEs) are a major driver of plant genome evolution. A part frombeing a rich source of new genes and regulatory sequences, TEs can also affect plant genome evolution by modifying genome size and shaping chromosome structure. TEs tend to concentrate in heterochromatic pericentromeric regions and their proliferation may expand these regions. Here, we show that after the split of melon and cucumber, TEs have expanded the pericentromeric regions of melon chromosomes that, probably as a consequence, show a very low recombination frequency. In contrast, TEs have not proliferated to a high extent in cucumber, which has small TE-dense pericentromeric regions and shows a relatively constant recombination rate along chromosomes. These differences in chromosome structure also translate in differences in gene nucleotide diversity. Although gene nucleotide diversity is essentially constant along cucumber chromosomes, melon chromosomes show a bimodal pattern of genetic variability, with a gene-poor region where variability is negatively correlated with gene density. Interestingly, genes are not homogeneously distributed in melon, and the high variable low-recombining pericentromeric regions show a higher concentration of melon-specific genes whereas genes shared with cucumber and other plants are essentially found in gene-rich chromosomal arms. The results presented here suggest that melon pericentromeric regions may allow gene sequences to evolve more freely than in other chromosomal compartments which may allow new ORFs to arise and eventually be selected. These results show that TEs can drastically change the structure of chromosomes creating different chromosomal compartments imposing different constraints for gene evolution.
Grants:	Ministerio de Economía y Competitividad AGL2013-43244-R Ministerio de Economía y Competitividad AGL2015-64625-C2-1-R Ministerio de Economía y Competitividad AGL2016-78992-R
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Heterochromatin ; Recombination ; Transposon ; Genetic variability
Published in:	Genome biology and evolution, Vol. 10, Núm. 6 (June 2018) , p. 1584-1595, ISSN 1759-6653

DOI: 10.1093/gbe/evy115
PMID: 29901717

12 p, 836.9 KB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > CRAG (Centre for Research in Agricultural Genomics)
Articles > Research articles
Articles > Published articles