Population biology of Avena (original) (raw)

Summary

Surveys for polymorphisms in natural populations of A. barbata sampled in California grasslands had provided evidence for widespread monomorphism and rather localized polymorphic areas in the north coastal and San Francisco regions, based on a set of morphological and isoenzymatic marker loci. Since this species, like many other annuals, was introduced from the Mediterranean region during the Spanish mission period, a comparative study of the Canadian-Welsh collections of Avena species from the Mediterranean region was undertaken using various plant characters and starch gel electrophoresis to analyze variants for esterase, phosphatase and peroxidase systems. A total of 96 samples including 73 of A. barbata and 23 of A. hirtula were studied and the results were scored to compute the polymorphism indices. In both species, only 10 to 15 percent sites showed any significant degree of polymorphism of which a majority seemed to originate from localized regions in Italy and Turkey; a part of this observed lack of within-sample variation might be the result of small sample size. In general, the patterns of variation in A. barbata from the California surveys and the present analyses seemed to be very similar and raised some interesting questions on (a) the colonizing history of introduced materials (b) the factors underlying such marked patterns of geographical variation, and (c) the current evolutionary changes occurring in these two broad, disjunct areas of species distribution.

Zusammenfassung

Untersuchungen der Polymorphismen in natürlichen Populationen von A. barbata im kalifornischen Weideland hatten einerseits zum Nachweis eines weit verbreiteten Monomorphismus und andererseits streng lokalisierter polymorpher Bereiche in der nördlichen Küsten- und San Francisco-Region geführt, wobei eine Anzahl morphologischer und isoenzymatischer Markerloci zugrunde gelegt wurde. Da diese Art, wie viele andere Annuelle auch, während der spanischen Missionsperiode aus der Mittelmeerregion eingeführt wurde, wurde eine vergleichende Untersuchung der Canadian-Welsh-Sammlungen von _Avena_-Arten aus der Mittelmeerregion anhand verschiedener Merkmale der Pflanzen und der Stärkegelelektrophorese-Untersuchung auf Esterase-, Phosphatase- und Peroxydase-Systeme durchgeführt. Es wurde eine Gesamtheit von 96 Stichproben, bestehend aus 73 A. barbata und 23 A. hirtula, untersucht und die Ergebnisse zur Berechnung von Polymorphismus-Indices verwendet. In beiden Arten zeigten nur 10 bis 15% der Herkünfte einen signifikanten Polymorphismusgrad. Von ihnen scheint die Mehrzahl von lokalisierten Regionen in Italien und Griechenland abzustammen. Ein Teil des beobachteten Fehlens einer Variation innerhalb der Stichproben könnte eine Folge des geringen Stichprobenumfangs sein. Im allgemeinen scheinen die Variationsmuster der kalifornischen Untersuchungen und die der vorliegenden Analysen von A. barbata sehr ähnlich zu sein. Das führt zu einigen interessanten Fragen nach a) der Besiedelungsgeschichte des eingeführten Materials, b) den Faktoren, die derart auffallenden Mustern der geographischen Variation unterliegen und c) den laufenden evolutionären Änderungen, die in diesen beiden großen, voneinander getrennten Gebieten der Artverteilung auftreten.

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Literature cited

  1. Ashburner, M.: On the problem of genetic similarity between sibling species — puffing patterns in Drosophila melanogaster and D. simulans. Amer. Natur. 103, 189 to 191 (1969).
    Google Scholar
  2. Brown, A. H. D.: The effect of reciprocal recurrent selection for yield, on isozyme polymorphisms in maize. Ph. D. Dissertation, Univ. of California, Davis (1969).
    Google Scholar
  3. Burcham, L. T.: California range land. Division of Forestry, State of California (1957).
  4. Hubby, J. L., Throckmorton, L. H.: Protein differences in Drosophila. IV. A study of sibling species. Amer. Natur. 102, 193–205 (1968).
    Google Scholar
  5. Jain, S. K.: Comparative ecogenetics of two Avena species occurring in Central California. Evol. Biol. 3, 73–118 (1969). — (Paper I in this series „Population Biology of _Avena_”).
    Google Scholar
  6. Jain, S. K., Marshall, D. R.: Population studies in predominantly self-pollinating species. X. Variation in natural populations of Avena fatua and A. barbata. Amer. Natur. 101, 19–33 (1967).
    Google Scholar
  7. Kristjansson, F. K.: Genetic control of two prealbumins in pigs. Genetics 48, 1059–1063 (1963).
    Google Scholar
  8. Ladizinsky, G., Zohary, D.: Genetic relationships between diploids and tetraploids in series Eubarbatae of Avena. Can. J. Genet. Cytol. 10, 68–81 (1968).
    Google Scholar
  9. Lewontin, R. C.: Population genetics. Ann. Rev. Genet. 1, 37–70 (1967).
    Google Scholar
  10. Lewontin, R. C., Hubby, J. L.: A molecular approach to the study of genic heterozygosity in natural populations. II. Amount of variation and degree of heterozygosity in natural populations of Drosophila pseudoobscura. Genetics 54, 595–609 (1966).
    Google Scholar
  11. Marshall, D. R., Allard, R. W.: The genetics of electrophoretic variants in Avena. I. The esterasc E4, E9, E10, phosphatase P5 and anodal peroxidase APX5 loci in A. barbata. J. Hered. 60, 17–19 (1969).
    Google Scholar
  12. Marshall, D. R., Allard, R. W.: Isozyme polymorphisms in natural populations of Avena fatua and A. barbata. Heredity (in press).
  13. Marshall, D. R., Jain, S. K.: Cohabitation and relative abundance of two species of wild oats. Ecology 48, 656–659 (1967).
    Google Scholar
  14. Naveh, Z.: Mediterranean ecosystems and vegetation types in California and Israel. Ecology 48, 445–459 (1967).
    Google Scholar
  15. Rajhathy, T., Morrison, J. W.: Genome homology in the genus Avena. Can. J. Genet. Cytol. 2, 278–285 (1960).
    Google Scholar
  16. Rajhathy, T., Thomas, H.: Chromosomal differentiation and speciation in diploid Avena. III. Mediterranean wild populations. Can. J. Genet. Cytol. 9, 52–68 (1967).
    Google Scholar
  17. Rajhathy, T., Zillinsky, F. J., Hayes, J. D.: A collection of wild oat species in the Mediterranean region. Canada Dept. Agr. Res. Sta., Ottawa (1966).
    Google Scholar
  18. Rendel, J., Stormont, C.: Variants of amine alkaline serum phosphatases and their association with the R-O blood groups. Proc. Soc. Exp. Biol. N. Y. 115, 853–856 (1964).
    Google Scholar
  19. Shaw, C. R., Koen, A. L.: Starch gel zone electrophoresis of enzymes. In: I. Smith (ed.), Chromatographic and Electrophoretic Techniques, pp. 325–364. New York: Interscience 1968.
    Google Scholar
  20. Spafford, J. B.: Heterosis and the evolution of duplications. Amer. Natur. 103, 407 to 432 (1969).
    Google Scholar
  21. Talbot, M. W., Biswell, H. H., Hormay, A. L.: Fluctuation in the annual vegetation at California. Ecology 20, 394–402 (1939).
    Google Scholar
  22. Watts, R. L., Watts, D. C.: Gene duplication and the evolution of enzymes. Nature, Lond. 217, 1125–1130 (1968).
    Google Scholar

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Authors and Affiliations

  1. Department of Agronomy and Range Science, University of California, Davis, California, USA
    R. S. Singh & S. K. Jain

Authors

  1. R. S. Singh
  2. S. K. Jain

Additional information

Communicated by W. Seyffert

This work was supported in part by a grant from the National Science Foundation (GB 8627).

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Singh, R.S., Jain, S.K. Population biology of Avena.Theoret. Appl. Genetics 41, 79–84 (1971). https://doi.org/10.1007/BF00277049

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