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Hybrid sterility and inviability in the parasitic fungal species complex Microbotryum
Author(s) -
DE VIENNE D. M.,
REFRÉGIER G.,
HOOD M. E.,
GUIGUE A.,
DEVIER B.,
VERCKEN E.,
SMADJA C.,
DESEILLE A.,
GIRAUD T.
Publication year - 2009
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/j.1420-9101.2009.01702.x
Subject(s) - biology , reproductive isolation , assortative mating , selfing , mating , sterility , genetic divergence , mating system , hybrid , host (biology) , evolutionary biology , zoology , genetics , botany , genetic diversity , population , demography , sociology
Microbotryum violaceum , the anther‐smut fungus, forms a complex of sibling species which specialize on different plants. Previous studies have shown the presence of partial ecological isolation and F1 inviability, but did not detect assortative mating apart from a high selfing rate. We investigated other post‐mating barriers and show that F1 hybrid sterility, the inability of gametes to mate, increased gradually with the increasing genetic distance between the parents. F2 hybrids showed a reduced ability to infect the plants that was also correlated with the genetic distance. The host on which the F2 hybrids were passaged caused a selection for alleles derived from the pathogen species originally isolated from that host, but this effect was not detectable for the most closely related species. The post‐mating barriers thus remain weak among the closest species pairs, suggesting that premating barriers are sufficient to initiate divergence in this system.