Abstract
Inbreeding depression has been a topic of interest in recent years from a number of perspectives, particularly in the captive breeding of endangered species. Generally, the goal of captive breeding is to avoid the detrimental effects of inbreeding depression and to retain genetic variation for future adaptation. However, an important component of another suggested approach to captive breeding is to purge rapidly the population of its genetic load so that its long-term fitness is not compromised. I have examined the effectiveness of purging the genetic load by documenting both the reduction in inbreeding depression and the increase of the probability of extinction when there is continous full-sib mating. When the genetic load is the result of- lethals, the inbreeding depression is quickly purged without a high probability of extinction, except when the total genetic load is high. On the other hand, if the load is due to detrimentals of relatively small effect, the genetic load becomes fixed, the mean fitness is reduced, and the probability of extinction may be greatly increased. In other words, the success of such a programme to purge genetic load without an increase in the probability of extinction is highly dependent, upon the genetic basis of inbreeding depression, information that is not readily available for most species.
Similar content being viewed by others
Article PDF
References
Barrett, S C H, and Charlesworth, D. 1991. Effects of a change in the level of inbreeding on the genetic load. Nature, 352, 522–524.
Bittles, A H, Mason, W M, Greene, J, and Rao, N A. 1991. Reproductive behavior and health in consanguineous marriages. Science, 252, 789–794.
Bowman, J C, and Falconer, D S. 1960. Inbreeding depression and heterosis of litter size in mice. Genet Res, 1, 262–274.
Brown, A H D. 1979. Enzyme polymorphism in plant populations. Theor Pop Biol 15, 1–42.
Cavalli-Sforza, L L, and Bodmer, W F. 1971. The Genetics of Human Populations. W. H. Freeman, San Francisco.
Charlesworth, D, and Charlesworth, B. 1987. Inbreeding depression and its evolutionary consequences. Ann Rev Ecol Syst, 18, 237–268.
Charlesworth, D, Morgan, M T, and Charlesworth, B. 1992. The effect of linkage and population size on inbreeding depression due to mutational load. Genet Res, 59, 49–61.
Crow, J F, and Kimura, M. 1970. An Introduction to Population Genetics Theory. Harper and Row, New York.
Darwin, C R. 1868. Variation of Animals and Plants under Domestication. John Murray, London.
Darwin, C R. 1876. The Effects of Cross and Self Fertilization in the Vegetable Kingdom. John Murray, London.
Ehiobu, N G, Goddard, M E, and Taylor, J F. 1989. Effect of rate of inbreeding on inbreeding depression in Drosophila melanogaster. Theor Appl Genet, 77, 123–137.
Franklin, I R. 1980. Evolutionary changes in small populations. In: Soulé, M. E. and Wilcox, B. A. (eds) Conservation Biology, pp. 135–149. Sinauer, Sunderland, MA.
Haldane, J B S. 1937. Some theoretical results of continued brother-sister mating. J Genet, 34, 265–274.
Hedrick, P W. 1985. Genetics of Populations. Jones and Bartlett, Boston.
Hedrick, P W. 1990. Mating systems and evolutionary genetics. In: Wohrmann, K. and Jain, S. (eds) Population Biology: Ecological and Evolutionary Viewpoints, pp. 83–114. Springer, New York.
Hedrick, P W, and Miller, P S. 1992. Conservation genetics: techniques and fundamentals. Ecol Appl, 2, 30–46.
Kimura, M, and Maruyama, T. 1966. The mutational load with epistatic gene interactions in fitness. Genetics, 54, 1337–1351.
Lacy, R C. 1992. The effects of inbreeding on isolated populations: are minimum viable population sizes predictable? In: Fiedler, P. L and Jain, S. K. (eds) Conservation Biology: the Theory and Practice of Nature Conservation, Preservation and Management, pp. 277–296. Chapman and Hall, New York.
Lande, R, and Barrowclough, G F. 1987. Effective population size, genetic variation, and their use in population management. In: Soulé, M. E. (ed.) Viable Populations for Conservation, pp. 87–123. Cambridge University Press, Cambridge.
Lerner, I M. 1954. Genetic Homeostasis. Oliver and Boyd, Edinburgh.
Lynch, M, and Gabriel, W. 1990. Mutation load and the survival of small populations. Evolution, 44, 1725–1737.
Marinkovic, D. 1967. Genetic loads affecting fecundity in natural populations of D. pseudoobscura. Genetics, 56, 61–71.
Miller, P S, and Hedrick, P W. 1993. Inbreeding and fitness in captive populations: lessons from Drosophila. Zoo Biol, 12, 333–352.
Ralls, K, Ballou, J, and Templeton, A. 1988. Estimates of lethal equivalents and the cost of inbreeding in mammals. Conserv Biol, 2, 185–193.
Reeve, E C R. 1955. Inbreeding with homozygotes at a disadvantage. Ann. Rev Genet, 21, 277–288.
Sanghvi, L D. 1966. Inbreeding in India. Eugen Quart, 13, 291–301.
Sharp, P M. 1984. The effect of inbreeding on competitive male-mating ability in Drosophila melanogaster. Genetics, 106, 601–612.
Simmons, M J, and Crow, J F. 1977. Mutations affecting fitness in Drosophila populations. Ann Rev Genet, 11, 49–78.
Sittman, K, Abplanalp, H A, and Fisher, R A. 1966. Inbreeding depression in Japanese quail. Genetics, 54, 371–379.
Templeton, A R, and Read, B. 1983. The elimination of inbreeding depression in a captive herd of Speke's gazelle. In: Schonewald, C. M., Chambers, S. M., MacBryde, B. and Thomas, L. (eds) Genetics and Conservation, pp. 241–262. Benjamin/Cummings, Menlo Park, CA.
Templeton, A R, and Read, B. 1984. Factors eliminating inbreeding depression in a captive herd of Speke's gazelle. Zoo Biol, 3, 177–199.
Wright, S. 1977. Evolution and Genetics of Populations, vol 3 Experimental and Evolutionary Deductions. University of Chicago Press, Chicago.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Hedrick, P. Purging inbreeding depression and the probability of extinction: full-sib mating. Heredity 73, 363–372 (1994). https://doi.org/10.1038/hdy.1994.183
Received:
Issue Date:
DOI: https://doi.org/10.1038/hdy.1994.183
Keywords
This article is cited by
-
Self-fertilization does not lead to inbreeding depression in Typha parent species or hybrids
Evolutionary Ecology (2024)
-
Impact of genetic relatedness on reproductive behavior in Pelvicachromis pulcher, a biparental cichlid fish with mutual mate choice and ornamentation
The Science of Nature (2023)
-
Reviewing the consequences of genetic purging on the success of rescue programs
Conservation Genetics (2022)
-
Grid search approach to discriminate between old and recent inbreeding using phenotypic, pedigree and genomic information
BMC Genomics (2021)
-
Long-term exhaustion of the inbreeding load in Drosophila melanogaster
Heredity (2021)