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PubMed · 40253498

Does chromoanagenesis play a role in the origin of B chromosomes?

Andreas Houben·Jörg Fuchs·Ali Mohammad Banaei-Moghaddam·Jianyong Chen·Gihwan Kim·Taoran Liu
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Abstract

B chromosomes (Bs) exist in addition to the standard (A) chromosomes in a wide range of species. The process underlying their origin is still unclear. We propose pathways of intra- and interspecific origin of B chromosomes based on known mechanisms of chromosome evolution and available knowledge of their sequence composition in different species. We speculate that a mitotic or meiotic segregation error of one or more A chromosomes initiates, via chromoanagenesis, the formation of a proto-B chromosome. In the second step, proto-B chromosomes accumulate A chromosome- and organelle-derived sequences over time, most likely via DNA double-strand break (DSB) mis-repair. Consequently, the original structure of the early stage proto-B chromosomes becomes masked by continuous sequence incorporation. The similarity between A chromosome sequences integrated into B chromosomes and the original sequences on the donor chromosomes decreases over time if there is no selection pressure on these sequences on B chromosomes. However, besides chromoanagenesis, also other mechanisms leading to the formation of B chromosomes might exist.

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Evolution, MolecularAnimalsChromosomesMeiosisDNA Breaks, Double-StrandedJournal ArticleReview

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Andreas Houben, Jörg Fuchs, Ali Mohammad Banaei-Moghaddam, Jianyong Chen, Gihwan Kim, Taoran Liu. 2025-04-19. Does chromoanagenesis play a role in the origin of B chromosomes?. https://doi.org/10.1038/s41437-025-00758-w

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