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REDUCED MALE FERTILITY IS COMMON BUT HIGHLY VARIABLE IN FORM AND SEVERITY IN A NATURAL HOUSE MOUSE HYBRID ZONE
Author(s) -
Turner Leslie M.,
Schwahn Denise J.,
Harr Bettina
Publication year - 2012
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.2011.01445.x
Subject(s) - biology , house mouse , natural (archaeology) , house mice , fertility , evolutionary biology , demography , ecology , zoology , paleontology , population , sociology
Barriers to gene flow between naturally hybridizing taxa reveal the initial stages of speciation. Reduced hybrid fertility is a common feature of reproductive barriers separating recently diverged species. In house mice ( Mus musculus ), hybrid male sterility has been studied extensively using experimental crosses between subspecies. Here, we present the first detailed picture of hybrid male fertility in the European M. m. domesticus — M. m. musculus hybrid zone. Complete sterility appears rare or absent in natural hybrids but a large proportion of males (∼30%) have sperm count or relative testis weight below the range in pure subspecies, and likely suffer reduced fertility. Comparison of a suite of traits related to fertility among subfertile males indicates reduced hybrid fertility in the contact zone is highly variable among individuals and ancestry groups in the type, number, and severity of spermatogenesis defects present. Taken together, these results suggest multiple underlying genetic incompatibilities are segregating in the hybrid zone, which likely contribute to reproductive isolation between subspecies.