PT  - JOURNAL ARTICLE
AU  - Boman, Jesper
AU  - Näsvall, Karin
AU  - Vila, Roger
AU  - Wiklund, Christer
AU  - Backström, Niclas
TI  - Evolution of hybrid inviability associated with chromosome fusions
AID  - 10.1101/2023.11.30.569355
DP  - 2023 Jan 01
TA  - bioRxiv
PG  - 2023.11.30.569355
4099  - http://biorxiv.org/content/early/2023/12/01/2023.11.30.569355.short
4100  - http://biorxiv.org/content/early/2023/12/01/2023.11.30.569355.full
AB  - Chromosomal rearrangements, such as inversions, have received considerable attention in the speciation literature due to their hampering effects on recombination. However, less is known about how other rearrangements, such as chromosome fissions and fusions, can affect the evolution of reproductive isolation. Here, we used crosses between populations of the wood white butterfly (Leptidea sinapis) with different karyotypes to identify genomic regions associated with hybrid inviability. By contrasting allele frequencies between F2 hybrids that survived until the adult stage with individuals of the same cohort that succumbed to hybrid incompatibilities, we show that candidate loci for hybrid inviability mainly are situated in fast-evolving regions with reduced recombination rates, especially in regions where chromosome fusions have occurred. Our results show that the extensive variation in chromosome numbers observed across the tree of life can be involved in speciation by being hotspots for the early evolution of postzygotic reproductive isolation.Competing Interest StatementThe authors have declared no competing interest.