Abstract
We report here a study of viability inbreeding depression associated with the X chromosome of Drosophila melanogaster. Fifty wild chromosomes from Mt. Sinai, New York, and 90 wild chromosomes from Death Valley, California, were extracted using the marked FM6 balancer chromosome and viabilities measured for homozygous and heterozygous females, and for hemizygous males, relative to FM6 males as a standard genotype. No statistically significant female genetic load was observed for either chromosome set, although a 95% confidence limit estimated the total load <0.046 for the samples pooled. About 10% of the Death Valley chromosomes appear to be "supervital" as homozygotes. There is little evidence for a pervasive sex-limited detrimental load on the X chromosome; the evidence indicates nearly identical viability effects in males and homozygous females excluding the supervital chromosomes. The average degree of dominance for viability polygenes is estimated between 0.23 to 0.36, which is consistent with autosomal variation and implies near additivity. We conclude that there is little genetic load associated with viability variation on the X chromosome and that the substantial reduction in total fitness observed for chromosome homozygosity in an earlier study may be due largely to sex-limited fertility in females.
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Selected References
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- Bossy B., Hall L. M., Spierer P. Genetic activity along 315 kb of the Drosophila chromosome. EMBO J. 1984 Nov;3(11):2537–2541. doi: 10.1002/j.1460-2075.1984.tb02169.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Engels W. R. The P family of transposable elements in Drosophila. Annu Rev Genet. 1983;17:315–344. doi: 10.1146/annurev.ge.17.120183.001531. [DOI] [PubMed] [Google Scholar]
- Hiraizumi Y. A model of the negative correlation between male recombination and transmission frequency in Drosophila melanogaster. Genetics. 1979 Oct;93(2):449–459. doi: 10.1093/genetics/93.2.449. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Matthews K. A., Hiraizumi Y. An Analysis of Male-Recombination Elements in a Natural Population of DROSOPHILA MELANOGASTER in South Texas. Genetics. 1978 Jan;88(1):81–91. doi: 10.1093/genetics/88.1.81. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Morton N. E., Crow J. F., Muller H. J. AN ESTIMATE OF THE MUTATIONAL DAMAGE IN MAN FROM DATA ON CONSANGUINEOUS MARRIAGES. Proc Natl Acad Sci U S A. 1956 Nov;42(11):855–863. doi: 10.1073/pnas.42.11.855. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mukai T., Cardellino R. A., Watanabe T. K., Crow J. F. The genetic variance for viability and its components in a local population of Drosophila melanogaster. Genetics. 1974 Dec;78(4):1195–1208. doi: 10.1093/genetics/78.4.1195. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mukai T., Chigusa S. I., Mettler L. E., Crow J. F. Mutation rate and dominance of genes affecting viability in Drosophila melanogaster. Genetics. 1972 Oct;72(2):335–355. doi: 10.1093/genetics/72.2.335. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mukai T., Yamaguchi O. The genetic structure of natural populations of Drosophila melanogaster. XI. Genetic variability in a local population. Genetics. 1974 Feb;76(2):339–366. doi: 10.1093/genetics/76.2.339. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Simmons M. J., Crow J. F. Mutations affecting fitness in Drosophila populations. Annu Rev Genet. 1977;11:49–78. doi: 10.1146/annurev.ge.11.120177.000405. [DOI] [PubMed] [Google Scholar]
- Tracey M. L., Ayala F. J. Genetic load in natural populations: is it compatible with the hypothesis that many polymorphisms are maintained by natural selection? Genetics. 1974 Jul;77(3):569–589. doi: 10.1093/genetics/77.3.569. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wilton A. N., Sved J. A. X-chromosomal heterosis in Drosophila melanogaster. Genet Res. 1979 Dec;34(3):303–315. doi: 10.1017/s0016672300019534. [DOI] [PubMed] [Google Scholar]