Abstract
The potential factors that may influence the genetic structure of the gynodioecious annual Phacelia dubia were assessed using electrophoretic and ecological information at a locality in which the population size changed by about three orders of magnitude. Fluctuations in population size appeared to have little influence on the allelic composition, heterozygosity and mixed mating system of the population. Despite wide fluctuations in total population size, the estimated effective population size during (Ne = 20) and after the bottleneck (Ne = 28) was little changed. Also, a significant spatial substructuring, evidenced by a cline in MDH and by the F-statistics, was observed before and after the bottleneck. The recovery of the population and the preservation of genetic diversity was attributable in part to the seed bank in the soil. Spatial gene flow via seeds was small compared with pollen flow and both were restricted. Nevertheless, substructuring contributes to a small portion of the total inbreeding. Also, the rate of apparent selfing of male steriles did not provide evidence of biparental inbreeding. Most of the inbreeding, however, was within subpopulations and autogamy appears to be the major contributor. It was concluded that the mating system is the leading factor determining the genetic structure and that the seed bank ensures genetic constancy in time in the face of large fluctuations in population size.
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Allard, R W. 1975. The mating system and microevolution. Genetics, 79, 115–126.
Augspurger, C K. 1980. Mass-flowering of a tropical shrub (Hybanthus prunifolious): influence of pollinator attraction and movement. Evolution, 34, 475–488.
Bailey, N T J. 1961. Introduction to the Theory of Genetic Linkage. Oxford University Press, London.
Baskin, J M, and Baskin, C C. 1973. Delayed germination in seeds of Phacelia dubia var dubia. Can J Bot, 51, 2481–2486.
Baskin, J M, and Baskin, C C. 1978. Role of temperature in the regulation of the life cycle of the winter annual Phacelia dubia var. dubia in the Tennessee Cedar Glades. J Tenn Acad Sci, 53, 118–120.
Betancourt, J L, Schuster, W S, Mitton, J B, and Anderson, R S. 1991. Fossil and genetic history of a pinyon pine (Pinus edulis) isolate. Ecology, 72, 1685–1697.
Brown, A H D. 1979. Enzyme polymorphism in plant populations. Theor Pop Biol, 15, 1–42.
Burrows, F M. 1986. The aerial motion of seeds, fruits, spores and pollen. In: Murray, D. R. (ed.) Seed Dispersal, pp. 2–47. Academic Press, Sydney.
Chambers, J C, Macmahon, J A, and Haefner, J H. 1991. Seed entrapment in alpine ecosystems: effects of soil particle size and diaspora morphology. Ecology, 72, 1668–1677.
Charlesworth, D. 1991. The apparent selection on neutral marker loci in partially inbreeding populations. Gen Res, 57, 159–175.
Cheliak, W M, Dancik, B P, Morgan, K, Yeh, F C H, and Strobeck, C. 1985. Temporal variation of the mating system in a natural population of Jack Pine. Genetics, 109, 569–584.
Clegg, M T. 1980. Measuring plant mating systems: BioScience, 30, 814–818.
Clegg, M T, and Allard, R W. 1972. Patterns of genetic differentiation in the slender wild oat species Avena barbata. Proc Natl Acad Sci USA, 69, 1820–1824.
Cockerham, C C. 1969. Variance in gene frequencies. Evolution, 23, 72–84.
Conover, W J. 1980. Practical Nonparametric Statistics. John Wiley, New York.
Cook, R. 1980. The biology of seeds in the soil. In: Solbrig, O. T. (ed.) Demography and Evolution in Plant Populations, pp. 107–129. Blackwell Scientific Publications, Oxford.
Crow, J F, and Aoki, K. 1984. Group selection for a polygenic behavioral trait: estimation of the degree of population subdivision. Proc Natl Acad Sci USA, 81, 6073–6077.
Crow, J F, and Kimura, M. 1970. An Introduction to Population Genetics Theory. Harper and Row, New York.
Cugen, J, Merzeau, D, and Thiebaut, B. 1988. Genetic structure of the European beech stands (Fagus sylvatica L.): F-statistics and importance of mating systems characteristics in their evolution. Heredity, 60, 91–100.
Del Castillo, R F. 1992. Breeding system consequence in Phacelia dubia. Ph. D Thesis, Duke University.
Del Castillo, R F. 1993. Consequences of male sterility in Phacelia dubia. Evol Tre Pl, 7, 15–22.
Dewey, S E, and Heywood, J S. 1988. Spatial genetic structure in a population of Psychotria nerviosa. I. Distribution of genotypes. Evolution, 42, 834–838.
Ellstrand, N C, and Foster, K W. 1983. Impact of population structure on the apparent outcrossing rate of grain sorghum (Sorghum bicolor). Theor Appl Genet, 66, 323–327.
Ennos, R A, and Clegg, M T. 1982. Effect of population sub-structuring on estimates of outcrossing rate in plant populations. Heredity, 48, 283–292.
Epling, C, Lewis, H, and Ball, F M. 1960. The breeding group and seed storage: a study in population dynamics. Evolution, 14, 238–255.
Fenster, C B. 1991. Gene flow in Chamaecrista fasciculata (Leguminosae). I. Gene dispersal. Evolution, 45, 398–409.
Fowler, D P, and Morris, R W. 1977. Genetic diversity in red pine: evidence for low genetic heterozygosity. Can J For Res, 7, 343–347.
Freeman, D H. 1987. Applied Categorical Data Analyses. Mercel Dekker, New York.
Fu, Y B, Knowles, P, and Perry, D J. 1992. Pollen pool heterogeneity in jack pine (Pinus banksiana Lamb.): a problem for estimating outcrossing rates. Theor Appl Genet, 83, 500–508.
Gottlieb, L D. 1974. Genetic stability in a peripheral isolate of Stephanomeria exigua ssp. coronaria that fluctuates in population size. Genetics, 76, 551–556.
Gouyon, P H, Vichot, F, and Van Damme, J M M. 1991. Nucleocytoplasmic male sterility: single point equilibria versus limit cycles. Am Nat, 137, 498–515.
Haldane, J B S. 1949. The association of characters as a result of inbreeding and linkage. Ann Eugen, 15, 15–23.
Handel, S N. 1983a. Pollination ecology, plant population structure and gene flow. In: Real, L. E. (ed.) Pollination Biology, pp. 163–211. Academic Press, Orlando.
Handel, S N. 1983b. Contrasting gene flow patterns and genetic subdivision in adjacent populations of Cucumis sativus (Cucurbitaceae). Evolution, 37, 760–771.
Hedrick, P W. 1980. Hitchhiking: a comparison of linkage and partial selfing. Genetics, 94, 791–808.
Heywood, J S. 1991. Spatial analysis of genetic variation in plant populations. Ann Rev Ecol Syst, 22, 335–355.
Kimura, M, and Weiss, G H. 1964. The stepping stone model of population structure and the decrease of genetic correlation with distance. Genetics, 49, 561–576.
Lacy, R C. 1987. Loss of genetic diversity from managed populations: interacting effects of drift, mutation, immigration, selection and population subdivision. Conserv Biol, 1, 143–158.
Lee, T D. 1984. Effects of seed number per fruit on seed dispersal in Cassia fasciculata. Bot Gaz, 145, 136–139.
Lesica, P, and Allendorf, F W. 1992. Are small populations of plants worth preserving? Conserv Biol, 6, 135–139.
Lesica, P, Leary, R F, Allendorf, F W, and Bilderbak, D E. 1988. Lack of genetic diversity within and among populations of an endangered plant, Howellia aquatilis. Conserv Biol, 2, 275–282.
Levin. D A. 1981. Dispersal versus gene flow in plants. Ann Mo Bot Gard, 68, 233–253.
Levin, D A, and Kerster, H W. 1968. Local gene dispersal in Phlox. Evolution, 22, 130–139.
Levin, D A, and Kerster, H W. 1974. Gene flow in seed plants. Evol Biol, 7, 139–220.
Levy, F. 1988. Effects of pollen source and time of pollination on seed production and seed weight in Phacelia dubia and P. maculata (Hydrophyllaceae). Am Midl Nat, 119, 193–198.
Levy, F. 1989. Mechanisms of speciation in Phacelia. Ph. D Thesis, Duke University.
Levy, F. 1991. Morphological differentiation in Phacelia dubia and P. maculata. Rhodora, 93, 11–25.
Loveless, M D, and Hamrick, J L. 1984. Ecological determinants of genetic structure in plant populations. Ann Rev Ecol Syst, 15, 65–95.
Loveless, M D, and Hamrick, J L. 1987. Distribución de la variatión en especies de árboles tropicales. Rev Biol Trop, 35, 165–175.
Macarthur, R H, and Wilson, E O. 1967. The Theory of Island Biogeography. Princeton University Press, Princeton, NJ.
Mather, K. 1946. Statistical Analysis in Biology, 2nd edn. Interscience, New York.
Moran, G F, and Brown, A H D. 1980. Temporal heterogeneity of outcrossing rates in alpine ash (Eucalyptus delegatensis R. T. Bak). Theor Appl Genet, 57, 101–105.
Murcia, C. 1990. Effect of floral morphology and temperature on pollen receipt and removal in Ipomoea trichocarpa. Ecology, 71, 1098–1109.
Murdy, W H. 1966. The systematics of Phacelia maculata and P. dubia var. georgiana, both endemic to granite outcrop communities. Am J Bot, 53, 1028–1036.
Nei, M, Maruyama, T, and Chakraborty, R. 1975. The bottleneck effect and genetic variability in populations. Evolution, 29, 1–10.
Ohta, T, and Cockerham, C C. 1974. Detrimental genes with partial selfing and effects on a neutral locus. Genet Res, 23, 191–200.
Price, M V, and Waser, N M. 1982. Experimental studies of pollen carryover: hummingbirds and Ipomopsis aggregata. Oecologia, 54, 353–358.
Prout, T. 1981. A note on the island model with sex dependent migration. Theor Appl Genet, 59, 327–332.
Pulliam, H R. 1988. Sources, sinks and population regulation. Am Nat, 132, 652–661.
Putman, P A. 1964. Speciation in Phacelia dubia. M. Sc. Thesis, Emory University.
Ritland, K. 1984. The effective proportion of self-fertilization with consanguineous matings in inbred populations. Genetics, 106, 139–152.
Ritland, K, and Jain, S. 1981. A model for the estimation of outcrossing rate and gene frequencies using n independent loci. Heredity, 47, 35–52.
Sas Institute. 1987. SAS/STAT Guide for Personal Computers, Version 6. SAS Institute, Cary, NC.
Schaal, B A. 1975. Population structure and local differentiation in Lyatris cylindracea. Am Nat, 109, 511–528.
Schaal, B A. 1980. Measurement of gene flow in Lupinus texensis. Nature, 284, 450–451.
Schaal, B A, and Smith, W G. 1980. The apportionment of genetic variation within and among populations of Desmodium nudiflorum. Evolution, 34, 214–221.
Schwaegerle, K E, Garbutt, K, and Bazzaz, F A. 1986. Differentiation among nine populations of Phlox. I. Electrophoretic and quantitative variation. Evolution, 40, 506–517.
Selander, R K, and Whittam, T S. 1983. Protein polymorphisms and the genetic structure of populations. In: Nei, M. and Koehn, R. K. (eds) Evolution of Genes and Proteins, pp. 89–114. Sinauer Associates, Sunderland, MA.
Shaw, D V, Kahler, A L, and Allard, R W. 1981. A multilocus estimator of mating system parameters in plant populations. Proc Natl Acad Sci USA, 78, 1298–1302.
Slatkin, M. 1977. Gene flow and genetic drift in species subject to frequent local extinctions. Theor Pop Biol, 12, 253–262.
Slatkin, M. 1985. Gene flow in natural populations. Ann Rev Ecol Syst, 16, 393–430.
Slatkin, M. 1987. Gene flow and the geographic structure of natural populations. Science, 236, 787–792.
Snyder, T P, Stewart, D A, and Strickler, A F. 1985. Temporal analysis of breeding structure in jack pine (Pinus banksiana Lamb.) Can J For Res, 15, 1159–1166.
Soltis, D E, Haufer, C H, Darrow, D C, and Gastony, G J. 1983. Starch gel electrophoresis of ferns: a compilation of grinding buffers, gel and electrode buffers and staining schedules. Am Fern J, 73, 9–27.
Soltis, P S, and Soltis, D E. 1988. Genetic variation and population structure in the fern Blechnum spicant (Blechnaceae) from Western North America. Am J Bot, 75, 37–44.
Sun, M, and Ganders, F R. 1988. Mixed mating systems in Hawaiian Bidens. Evolution, 42, 516–527.
Taggart, J B, McNally, S F, and Sharp, P M. 1990. Genetic variability and differentiation among founder populations of the pitcher plant (Sarracenia purpurea L.) in Ireland. Heredity, 64, 177–183.
Templeton, A S, and Levin, D A. 1979. Evolutionary consequences of seed pools. Am Nat, 114, 232–249.
Trenberth, K E, Branstator, G W, and Arkin, P A. 1988. Origins of the 1988 North American drought. Science, 242, 1640–1645.
Turner, M E, Stephens, J C, and Anderson, W W. 1982. Homozygosity and patch structure in plant populations as a result of nearest-neighbour pollination. Proc Natl Acad Sci USA, 79, 203–207.
Waddington, K D. 1983. Foraging behavior of pollinators. In: Real, L. (ed.) Pollination Biology, pp. 213–239. Academic Press, Orlando.
Waser, N M. 1983. The adaptive nature of floral traits: ideas and evidence. In Real, L. (ed.) Pollination Biology, pp. 241–285. Academic Press, Orlando.
Watkinson, A R. 1978. The demography of a sand dune annual: Vulpia fasciculata. III. The dispersal of the seeds. J Ecoi, 66, 483–498.
Weir, B S. 1990. Genetic Data Analysis. Sinauer Associates, Sunderland, MA.
Weir, B S, and Cockerham, C C. 1984. Estimating F-statistics for the analysis of population structure. Evolution, 38, 1358–1370.
Wright, S. 1932. The roles of mutation, inbreeding, crossbreeding and selection in evolution. Proc Sixth Int Cong Gen, 1, 356–366.
Wright, S. 1946. Isolation by distance under diverse systems of mating. Genetics, 31, 39–59.
Wright, S. 1969. The Evolution and Genetics of Populations, 2, The Theory of Gene Frequencies. University of Chicago Press, Chicago.
Wright, S. 1977. The Evolution and Genetics of Populations, 3, Experimental Results and Evolutionary Deductions. University of Chicago Press, Chicago.
Wright, S. 1978. Variability Within and Among Natural Populations, 4, Experimental Results and Evolutionary Deductions. University of Chicago Press, Chicago.
Wright, S. 1988. Surface of selective values revisited. Am Nat, 131, 115–123.
Young, H J, and Stanton, M L. 1990. Influences of floral variation on pollen removal and seed production in wild radish. Ecology, 71, 536–547.
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Castillo, R. Factors influencing the genetic structure of Phacelia dubia, a species with a seed bank and large fluctuations in population size. Heredity 72, 446–458 (1994). https://doi.org/10.1038/hdy.1994.63
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