The long-term consequences of hybridization
Department of Genetics, University of Cambridge, UK
When genetically distinct populations meet and mate, the outcome depends on whether their alleles mix well together. If new high fitness genotypes can be produced, the long-term outcome could be population fusion or adaptive introgression; but if the alleles are incompatible, the outcome might be loss of local adaptation, or reinforcement selection for increased isolation. One problem is that the long-term effects of hybridization seem difficult to predict from its short-term effects. For example, very high fitness F1 are often followed by very unfit F2. The uncertainty about long-term outcomes helps to explain debates in conservation biology about the value of hybrid populations, founded through multi-origin translocations; and debates among crop breeders about whether heterosis might be “fixed”, so that the yield benefits of F1 hybrids might be transferred to recombinant inbred lines. I will present some theoretical results, developed as part of CeMEB’s LabEx program, aiming to increase the long-term predictability of hybridization.
1. De Sanctis B, Schneemann H, Welch JJ (2023). How does the mode of evolutionary divergence affect reproductive isolation? Peer Community Journal 3:e6.
2. Schneemann H, Munzur AD, Thompson KA, Welch JJ (2022). The diverse effects of phenotypic dominance on hybrid fitness. Evolution 76:2846-2863.
3. Simon A, Bierne N, Welch JJ (2018). Coadapted genomes and selection on hybrids: Fisher's geometric model explains a variety of empirical patterns. Evolution Letters 22:472-498.
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