Summary
Song dialects in White-crowned Sparrows (Zonotrichia ieucophrys nuttalli) may act as partial barriers to the free exchange of genes. Within a dialect population, a genetic neighbourhood comprises about 100 individuals. Other factors combine to reduce the effective number to less than 50. By Wright’s methods, the genetic divergence among subpopulations (Fst) expected in a population exhibiting this size effective number with neutral alleles is about an order of magnitude larger than the observed Fst calculated from electrophoretically detectable alleles. Natural selection may therefore be maintaining greater homogeneity within a dialect than expected by assuming that alleles are neutral. From the torus model of Maruyama, however, the expected Fst values are close to those observed, suggesting no major departures from panmixia within dialect populations. The degree of genetic isolation exhibited between dialect populations may provide an explanation for the more rapid rate of speciation in passerine birds.
Similar content being viewed by others
Article PDF
References
Baker, M C. 1975. Song dialects and genetic differences in white-crowned sparrows (Zonotrichia leucophrys). Evolution, 29, 226–241.
Baker, M C, and Mewaldt, L R. 1978. Song dialects as barriers to dispersal in white-crowned sparrows, Zonotrichia leucophrys nuttalli. Evolution, 32, 712–722.
Baker, M C, Mewaldt, L R, and Stewart, R M. Demography of White-crowned sparrows. Ecology, (in press).
Bray, O E, Kennelly, J J, and Guarino, J L. 1975. Fertility of eggs produced on territories of vasectomized red-winged blackbirds. Wil Bull, 87, 187–195.
Bulmer, M G. 1973. Inbreeding in the great tit. Heredity, 30, 313–325.
Bush, G L, Case, S M, Wilson, A C, and Patton, J L. 1977. Rapid speciation and chromosomal evolution in mammals. Proc Natl Acad Sci USA, 74, 3942–3946.
Cavalli-Sforza, L L, Kimura, M, and Barrai, I. 1966. The probability of consanguineous marriages. Genetics, 54, 37–60.
Chakraborty, R, and Nei, M. 1974. Dynamics of gene differentiation between incompletely isolated populations of unequal sizes. Theoret Pop Biol, 5, 456–469.
Chamberlain, B. 1972. Observations of breeding white-crowned sparrows. Point Reyes Bird Observatory, Newsletter No. 23.
Crow, J F, and Kimura, M. 1970. An Introduction to Population Genetics Theory. Harper & Row, New York.
Crow, J F, and Morton, N E. 1955. Measurement of gene frequency drift in small populations. Evolution, 9, 202–214.
Dittus, W P J, and Lemon, R E. 1969. Effects of song tutoring and acoustic isolation on the song repertoires of cardinals. Anim Behav, 17, 523–533.
Feldman, M W, and Cavalli-Sforza, L L. 1976. Cultural and biological evolutionary processes, selection for a trait under complex transmission. Theor Pop Biol, 9, 238–259.
Greenwood, P J, and Harvey, P H. 1978. Inbreeding and dispersal in the great tit. Nature, 271, 52–54.
Immelmann, K. 1975. Ecological significance of imprinting and early learning. Ann Rev Ecol Syst, 6, 15–37.
Lande, R. 1979. Effective deme sizes during long-term evolution estimated from rates of chromosomal rearrangement. Evolution, 31, 234–251.
Marler, P, and Tamura, M. 1962. Song “dialects” in three populations of white-crowned sparrows. Condor, 64, 368–377.
Marler, P, and Tamura, M. 1964. Culturally transmitted patterns of vocal behavior in sparrows. Science, 146, 1483–1486.
Maruyama, T. 1972. Rate of decrease of genetic variability in a two-dimensional continuous population of finite size. Genetics, 70, 639–651.
Mayr, E, and Amadon, D. 1951. A classification of recent birds. Amer Mus Novit, No. 1496.
McCracken, G F, and Bradbury, J W. 1977. Paternity and genetic heterogeneity in the polygynous bat, Phyllostomus hastatus. Science, 198, 303–306.
Moreau, R E. 1966. On estimates of the past numbers and of the average longevity of avian species. Auk, 83, 403–415.
Nei, M. 1975. Molecular Population Genetics and Evolution. American Elsevier Publ. Co., Inc. New York. 288 pp.
Nei, M, and Imaizumi, Y. 1966. Genetic structure of human populations II. Differentiation of blood group gene frequencies among isolated populations. Heredity, 21, 183–190, 344.
Nottebohm, F. 1969. The song of the Chingolo, Zonotrichia capensis, in Argentina: Description and evaluation of a system of dialects. Condor, 71, 299–315.
Nottebohm, F. 1972. The origins of vocal learning. Amer Natur, 106, 116–140.
Petrinovich, L, and Patterson, T L. 1978. Polygyny in the white-crowned sparrow (Zonotrichia leucophrys). Condor, 80, 99–100.
Ralph, C J, and Pearson, C A. 1971. Correlation of age, size of territory, plumage, and breeding success in white-crowned sparrows. Condor, 73, 77–80.
Slatkin, M. 1976. The rate of spread of an advantageous allele in a subdivided population.. In Population Genetics and Ecology, eds. S. Karlin and E. Nevo. Academic Press, New York.
Wilson, A C, White, T J, Carlson, S S, and Cherry, L M. 1977. Molecular evolution and cytogenetic evolution. In Human Cytogenetics: ICN-UCLA Symposia on Molecular and Cellular Biology, eds. R. S. Sparkes, D. E. Comings, and C. F. Fox. Academic Press, New York.
Wright, S. 1943. Isolation by distance. Genetics, 28, 114–138.
Wright, S. 1946. Isolation by distance under diverse systems of mating. Genetics, 31, 39–59.
Wright, S. 1949. Adaptation and selection. In Genetics, Paleontology and Evolution, eds. G. L. Jepson, G. G. Simpson, and E. Mayr. Princeton University Press, Princeton.
Wright, S. 1951. The genetical structure of populations. Ann Eugenics, 15, 323–354.
Acknowledgements
Acknowledgements.-I thank Professors James F. Crow, Motoo Kimura, Takeo Maruyama, and Thomas Uzzell for their comments on this paper and Ann ?. ?. Baker for discussions of ideas contained herein. Professor Maruyama kindly calculated Fs, for the torus model. Financial support was provided by National Science Foundation grant DEB-78-22657.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Baker, M. Effective population size in a songbird: some possible implications. Heredity 46, 209–218 (1981). https://doi.org/10.1038/hdy.1981.28
Received:
Issue date:
DOI: https://doi.org/10.1038/hdy.1981.28
