Translator Disclaimer
1 July 2009 From Clonal to Sexual Hybrids: Genetic Recombination Via Triploids in All-Hybrid Populations of Water Frogs
Author Affiliations +

Speciation via interspecific hybrids is very rare in animals, as compared to plants. Whereas most plants overcome the problem of meiosis between different chromosome sets by tetraploidization, animal hybrids often escape hybrid sterility by clonal reproduction. This comes at the expense of genetic diversity and the ability to purge deleterious mutations. However, here we show that all-hybrid populations of diploid (LR) and triploid (LLR and LRR) water frogs (Pelophylax esculentus) have secondarily acquired sexual reproduction. First, in a crossing experiment analyzed with microsatellite markers, triploid hybrids of both sexes and genotypes (LLR and LRR) recombined their homospecific genomes. Second, the great majority of natural populations investigated had low multilocus linkage disequilibrium, indicating a high recombination rate. As predicted from mating system models, the L genome had constant, low levels of linkage disequilibrium, whereas linkage disequilibrium in the R genome showed a significant reduction with increasing proportion of recombining triploids. This direct evidence of sexual reproduction in P. esculentus calls for a change of the conventional view of hybridogens as clonally reproducing diploids. Rather, hybridogens can be independent sexually reproducing units with an evolutionary potential.

©2009 The Society for the Study of Evolution.
Ditte G. Christiansen and Heinz-Ulrich Reyer "From Clonal to Sexual Hybrids: Genetic Recombination Via Triploids in All-Hybrid Populations of Water Frogs," Evolution 63(7), 1754-1768, (1 July 2009).
Received: 9 December 2008; Accepted: 1 February 2009; Published: 1 July 2009

This article is only available to subscribers.
It is not available for individual sale.

Get copyright permission
Back to Top