Abstract
A new maximum-likelihood method is developed for estimating unidirectional pollen and seed flow in mixed-mating plant populations from counts of joint nuclear-cytoplasmic genotypes. Data may include multiple unlinked nuclear markers with a single maternally or paternally inherited cytoplasmic marker, or with two cytoplasmic markers inherited through opposite parents, as in many conifer species. Migration rate estimates are based on fitting the equilibrium genotype frequencies under continent-island models of plant gene flow to the data. Detailed analysis of their equilibrium structures indicates when each of the three nuclear-cytoplasmic systems allows gene flow estimation and shows that, in general, it is easier to estimate seed than pollen migration. Three-locus nuclear-dicytoplasmic data only increase the conditions allowing seed migration estimates; however, the additional dicytonuclear disequilibria allow more accurate estimates of both forms of gene flow. Estimates and their confidence limits for simulated data sets confirm that two-locus data with paternal cytoplasmic inheritance provide better estimates than those with maternal inheritance, while three-locus dicytonuclear data with three modes of inheritance generally provide the most reliable estimates for both types of gene flow. Similar results are obtained for hybrid zones receiving pollen and seed flow from two source populations. An estimation program is available upon request.
Full Text
The Full Text of this article is available as a PDF (263.0 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Asmussen M. A., Arnold J., Avise J. C. The effects of assortative mating and migration on cytonuclear associations in hybrid zones. Genetics. 1989 Aug;122(4):923–934. doi: 10.1093/genetics/122.4.923. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Asmussen M. A., Orive M. E. The effects of pollen and seed migration on nuclear-dicytoplasmic systems. I. Nonrandom associations and equilibrium structure with both maternal and paternal cytoplasmic inheritance. Genetics. 2000 Jun;155(2):813–831. doi: 10.1093/genetics/155.2.813. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Barton N. H., Turelli M. Natural and sexual selection on many loci. Genetics. 1991 Jan;127(1):229–255. doi: 10.1093/genetics/127.1.229. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Birky C. W., Jr, Fuerst P., Maruyama T. Organelle gene diversity under migration, mutation, and drift: equilibrium expectations, approach to equilibrium, effects of heteroplasmic cells, and comparison to nuclear genes. Genetics. 1989 Mar;121(3):613–627. doi: 10.1093/genetics/121.3.613. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Birky C. W., Jr, Maruyama T., Fuerst P. An approach to population and evolutionary genetic theory for genes in mitochondria and chloroplasts, and some results. Genetics. 1983 Mar;103(3):513–527. doi: 10.1093/genetics/103.3.513. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dong J., Wagner D. B. Paternally inherited chloroplast polymorphism in Pinus: estimation of diversity and population subdivision, and tests of disequilibrium with a maternally inherited mitochondrial polymorphism. Genetics. 1994 Mar;136(3):1187–1194. doi: 10.1093/genetics/136.3.1187. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Goodisman M. A., Asmussen M. A. Cytonuclear theory for haplodiploid species and X-linked genes. I. Hardy-Weinberg dynamics and continent-island, hybrid zone models. Genetics. 1997 Sep;147(1):321–338. doi: 10.1093/genetics/147.1.321. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hu X. S., Ennos R. A. Impacts of seed and pollen flow on population genetic structure for plant genomes with three contrasting modes of inheritance. Genetics. 1999 May;152(1):441–450. doi: 10.1093/genetics/152.1.441. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Latta R. G., Mitton J. B. A comparison of population differentiation across four classes of gene marker in limber pine (Pinus flexilis James). Genetics. 1997 Jul;146(3):1153–1163. doi: 10.1093/genetics/146.3.1153. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schnabel A., Asmussen M. A. Comparative effects of pollen and seed migration on the cytonuclear structure of plant populations. II. Paternal cytoplasmic inheritance. Genetics. 1992 Sep;132(1):253–267. doi: 10.1093/genetics/132.1.253. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sites J. W., Jr, Basten C. J., Asmussen M. A. Cytonuclear genetic structure of a hybrid zone in lizards of the Sceloporus grammicus complex (Sauria, Phrynosomatidae). Mol Ecol. 1996 Jun;5(3):379–392. [PubMed] [Google Scholar]
- Turelli M., Barton N. H. Genetic and statistical analyses of strong selection on polygenic traits: what, me normal? Genetics. 1994 Nov;138(3):913–941. doi: 10.1093/genetics/138.3.913. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wagner D. B., Furnier G. R., Saghai-Maroof M. A., Williams S. M., Dancik B. P., Allard R. W. Chloroplast DNA polymorphisms in lodgepole and jack pines and their hybrids. Proc Natl Acad Sci U S A. 1987 Apr;84(7):2097–2100. doi: 10.1073/pnas.84.7.2097. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Zouros E., Freeman K. R., Ball A. O., Pogson G. H. Direct evidence for extensive paternal mitochondrial DNA inheritance in the marine mussel Mytilus. Nature. 1992 Oct 1;359(6394):412–414. doi: 10.1038/359412a0. [DOI] [PubMed] [Google Scholar]
- Zouros E., Oberhauser Ball A., Saavedra C., Freeman K. R. An unusual type of mitochondrial DNA inheritance in the blue mussel Mytilus. Proc Natl Acad Sci U S A. 1994 Aug 2;91(16):7463–7467. doi: 10.1073/pnas.91.16.7463. [DOI] [PMC free article] [PubMed] [Google Scholar]
- el Mousadik A., Petit R. J. Chloroplast DNA phylogeography of the argan tree of Morocco. Mol Ecol. 1996 Aug;5(4):547–555. doi: 10.1111/j.1365-294x.1996.tb00346.x. [DOI] [PubMed] [Google Scholar]