Patterns of male sterility in a grasshopper hybrid zone imply accumulation of hybrid incompatibilities without selection.
Proc Biol Sci
; 272(1580): 2491-7, 2005 Dec 07.
Article
em En
| MEDLINE
| ID: mdl-16271974
ABSTRACT
It is now widely accepted that post-zygotic reproductive isolation is the result of negative epistatic interactions between derived alleles fixed independently at different loci in diverging populations (the Dobzhansky-Muller model). What is less clear is the nature of the loci involved and whether the derived alleles increase in frequency through genetic drift, or as a result of natural or sexual selection. If incompatible alleles are fixed by selection, transient polymorphisms will be rare and clines for these alleles will be steep where divergent populations meet. If they evolve by drift, populations are expected to harbour substantial genetic variation in compatibility and alleles will introgress across hybrid zones once they recombine onto a genetic background with which they are compatible. Here we show that variation in male sterility in a naturally occurring Chorthippus parallelus grasshopper hybrid zone conforms to the neutral expectations. Asymmetrical clines for male sterility have long tails of introgression and populations distant from the zone centre show significant genetic variation for compatibility. Our data contrast with recent observations on 'speciation genes' that have diverged as a result of strong natural selection.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Genética Populacional
/
Gafanhotos
/
Hibridização Genética
Tipo de estudo:
Risk_factors_studies
Limite:
Animals
País/Região como assunto:
Europa
Idioma:
En
Revista:
Proc Biol Sci
Assunto da revista:
BIOLOGIA
Ano de publicação:
2005
Tipo de documento:
Article
País de afiliação:
Reino Unido