Fitness landscapes support the dominance theory of post-zygotic isolation in the mussels Mytilus edulis and M. galloprovincialis
|Author(s)||Bierne Nicolas1, Bonhomme Francois1, Boudry Pierre2, Szulkin M1, David Pierre3|
|Affiliation(s)||1 : UMII, CNRS, UMR 5171,Stn Mediterraneenne Environm Littoral, IFREMER,Lab Genome Populat Interact Adaptat, F-34200 Sete, France.
2 : CNRS, CEFE, F-34293 Montpellier, France.
3 : IFREMER, Lab Genet & Pathol, F-17390 La Tremblade, France.
|Source||Proceedings of the Royal society of London (B) (Biological sciences) (0962-8452) (Royal Society of London), 2006-05 , Vol. 273 , N. 1591 , P. 1253-1260|
|WOS© Times Cited||51|
|Keyword(s)||Mytilus, Dobzhansky Muller incopatibilities, Post zygotic isolation, Negative epistasis, Hybrid breakdown, Hybrid zone|
|Abstract||We studied the genetic basis of post-zygotic isolation in the marine mussels Mytilus edulis and Mytilus galloprovincialis. Evidence was obtained for a high number of recessive Dobzhansky-Muller substitutions in the genome of these two mussel taxa. We analysed the segregation of unlinked diagnostic markers in the progeny of two backcrosses and an F-2 cross, 36 h and 200 days after fertilization. Directional selection favouring M. galloprovincialis genotypes was observed in both kinds of cross. In the F-2, epistatic interactions between each pair of chromosome fragments mapped by the markers were identified in addition. Our results imply that homozygous-homozygous interactions are required for breakdown of coadaptation, in accordance with the dominance theory of post-zygotic isolation. Endogenous post-zygotic selection distributed over many loci throughout the genome provides the missing factor explaining the astonishing persistence and strength of barriers to neutral introgression in such a dispersive taxon as Mytilus.|