Abstract
Gynodioecy, the coexistence of functionally female and hermaphroditic morphs within plant populations, often has a complicated genetic basis involving several cytoplasmic male-sterility factors and nuclear restorers. This complexity has made it difficult to study the genetics and evolution of gynodioecy in natural populations. We use a quantitative genetic analysis of crosses within and among populations of Silene vulgaris to partition genetic variance for sex expression into nuclear and cytoplasmic components. We also use mitochondrial markers to determine whether cytoplasmic effects on sex expression can be traced to mitochondrial variance. Cytoplasmic variation and epistatic interactions between nuclear and cytoplasmic loci accounted for a significant portion of the variation in sex expression among the crosses. Source population also accounted for a significant portion of the sex ratio variation. Crosses among populations greatly enhanced the dam (cytoplasmic) effect, indicating that most among-population variance was at cytoplasmic loci. This is supported by the large among-population variance in the frequency of mitochondrial haplotypes, which also accounted for a significant portion of the sex ratio variance in our data. We discuss the similarities between the population structure we observed at loci that influence sex expression and previous work on putatively neutral loci, as well as the implications this has for what mechanisms may create and maintain population structure at loci that are influenced by natural selection.
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Selected References
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- Bowe L. M., Coat G., dePamphilis C. W. Phylogeny of seed plants based on all three genomic compartments: extant gymnosperms are monophyletic and Gnetales' closest relatives are conifers. Proc Natl Acad Sci U S A. 2000 Apr 11;97(8):4092–4097. doi: 10.1073/pnas.97.8.4092. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Charlesworth D., Laporte V. The male-sterility polymorphism of Silene vulgaris: analysis of genetic dat from two populations and comparison with Thymus vulgaris. Genetics. 1998 Nov;150(3):1267–1282. doi: 10.1093/genetics/150.3.1267. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cho Y., Qiu Y. L., Kuhlman P., Palmer J. D. Explosive invasion of plant mitochondria by a group I intron. Proc Natl Acad Sci U S A. 1998 Nov 24;95(24):14244–14249. doi: 10.1073/pnas.95.24.14244. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Couvet D., Ronce O., Gliddon C. The maintenance of nucleocytoplasmic polymorphism in a metapopulation: the case of gynodioecy. Am Nat. 1998 Jul;152(1):59–70. doi: 10.1086/286149. [DOI] [PubMed] [Google Scholar]
- Hurst L. D., Atlan A., Bengtsson B. O. Genetic conflicts. Q Rev Biol. 1996 Sep;71(3):317–364. doi: 10.1086/419442. [DOI] [PubMed] [Google Scholar]
- Koelewijn H. P., Van Damme J. M. Genetics of male sterility in gynodioecious Plantago coronopus. I. Cytoplasmic variation. Genetics. 1995 Apr;139(4):1749–1758. doi: 10.1093/genetics/139.4.1749. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Koelewijn H. P., Van Damme J. M. Genetics of male sterility in gynodioecious Plantago coronopus. II. Nuclear genetic variation. Genetics. 1995 Apr;139(4):1759–1775. doi: 10.1093/genetics/139.4.1759. [DOI] [PMC free article] [PubMed] [Google Scholar]
- McCauley DE, Olson MS, Emery SN, Taylor DR. Population Structure Influences Sex Ratio Evolution in a Gynodioecious Plant. Am Nat. 2000 Jun;155(6):814–819. doi: 10.1086/303359. [DOI] [PubMed] [Google Scholar]
- de Haan A. A., Koelewijn H. P., Hundscheid M. P., Van Damme J. M. The dynamics of gynodioecy in Plantago lanceolata L. II. Mode of action and frequencies of restorer alleles. Genetics. 1997 Nov;147(3):1317–1328. doi: 10.1093/genetics/147.3.1317. [DOI] [PMC free article] [PubMed] [Google Scholar]