Population genetics in the American tropics XVII. The biogeographical position and the sampling technique as parameters of genetic loads inDrosophila
✍ Scribed by H. F. Hoenigsberg; M. M. E. Polanco; M. Ordoñez; H. C. Castañeda; C. A. Monje
- Publisher
- Springer Netherlands
- Year
- 1982
- Tongue
- English
- Weight
- 837 KB
- Volume
- 59
- Category
- Article
- ISSN
- 0016-6707
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✦ Synopsis
Biogeographically central populations of Drosophila melanogaster sampled with widespread and multiple sweepings generated in lethal equivalences very low indexes of heterozygous mortality which obviously produced a high B/A ratio. On the other hand, local samples from limited restricted sweepings within 10 m in diameter in a marginal population of D. willistonifrom the Macarena tropical rain forest have produced the highest indexes of heterozygous mortality and consequently a very low B/A ratio. Results reported here suggest that there are ecological constraints to the lethal-equivalence method, earlier proposed by Morton, Crow and Muller (1956, Proc. natn. A cad. Sci. U.S. A. 42: 8.55863). Moreover, the authors recommend that the sampling method reflect the ecological characteristic of the species under consideration.
The widespread sweeping-over-large-areas method of collecting Drosophila produces, in lethal-equivalent ratios, a degree of subvitality which must be interpreted as supporting the mutation-pressure theory. However, local sampling reveals loads compatible with the balancing-selection theory. The authors find that in their natural environments D. willistoni has a local genetical structure that supports the balancing-selection theory.