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HYBRID MALE STERILITY IN MIMULUS (PHRYMACEAE) IS ASSOCIATED WITH A GEOGRAPHICALLY RESTRICTED MITOCHONDRIAL REARRANGEMENT
Author(s) -
Case Andrea L.,
Willis John H.
Publication year - 2008
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.1558-5646.2008.00360.x
Subject(s) - biology , sterility , cytoplasmic male sterility , biological dispersal , outcrossing , population , evolutionary biology , gynodioecy , hybrid , nuclear gene , hybrid zone , mitochondrial dna , genetics , ecology , genetic variation , gene , gene flow , dioecy , botany , pollen , demography , sociology
Cytoplasmic male sterility (CMS) and nuclear fertility restoration ( Rf ) involves intergenomic coevolution. Although male‐sterile phenotypes are rarely expressed in natural populations of angiosperms, CMS genes are thought to be common. The evolutionary dynamics of CMS/ Rf systems are poorly understood, leaving gaps in our understanding of mechanisms and consequences of cytonuclear interactions. We characterized the molecular basis and geographic distribution of a CMS gene in Mimulus guttatus . We used outcrossing M. guttatus (with CMS and Rf ) to self‐fertilizing M. nasutus (lacking CMS and Rf ) to generate hybrids segregating for CMS. Mitochondrial transcripts containing an essential gene ( nad 6) were perfectly associated with male sterility. The CMS mitotype was completely absent in M. nasutus , present in all genotypes collected from the original collection site, but in only two individuals from 34 other M. guttatus populations. This pattern suggests that the CMS likely originated at a single locality, spread to fixation within the population, but has not spread to other populations, indicating possible ecological or genetic constraints on dispersal of this CMS mitotype between populations. Extreme localization may be characteristic of CMS in hermaphroditic species, in contrast to geographically widespread mitotypes commonly found in gynodioecious species, and could directly contribute to hybrid incompatibilities in nature.