S. Mahunka szerk.: Folia Entomologica Hungarica 48. (Budapest, 1987)

The highest level of polymorphism has been found at this locus during our investigations. Indices of polymorphism are almost twice as large as those of the other two species. In case of this species it is also clear that the highest level of polymorphism is in the Central Tisza Region (1). Mdhg in drosophila Immigrans Figure 10 shows the observed genotype frequencies. In Table 3 the allele frequencies are pre sented while in Table 5 the indices of polymorphism and genetic diversity. This is the only locus that has been found polymorphic in this species. These populations are mainly from the Bereg (NE) Plain (2) and as it has been assumed, indices of polymorphism and genetic diversities are in good agreement with the same values in D. hydei populations from the same region. Acknowledgements: - The author Is very grateful to Professor Z. VARGA for his helpful comments and suggestions during this study. The technical assistance of Miss M. BALOGH is also highly appreciated. REFERENCES BAND, H. T. (1975): A survey of isozyme polymorphism In a Drosophila melanogaster natural population. - Genetics, 80: 761-771. BATTERHAM, P., CHAMBERS, G. K., STARMER, W. T. and SULLIVAN, D. T. (1984): Origin and expression of an alcohol dehydrogenase gene duplication In the genus Drosophila. - Evolution, 38 (3): 644-657. BERGER, E. M. (1971): A temporal survey of allelic variation in natural and laboratory populations of Drosophila melanogaster. - Genetics, 67: 121-136. COURTRIGHT, J. B., IMBERSKI, R. B. and URSPRUNG, H. (1966): The genetic control of alcohol dehydrogenase and octanol dehydrogenase isozymes in Drosophila. - Genetics, 54: 1251-1260. GRELL, E.H., JACOBSON, K. B. and MURPHY, J. B. (1965): ADH in Drosophila melanogaster: Isozymes and genetic variants. - Science, 149

: 80-82. EL-HADIDY, Z. A. E. (1984): Geographical studies on allozyme and chromosomal variation in natural populations of Drosophila melanogaster. - Ph. D. Thesis: 64-73. IZSÁK, J. (1982): Diverzitási indexek összehasonlító vizsgálata mortalitási adatokon. Comparative investigations of diversity indices on mortality data . - Biológia, 30: 193-204. OAKESHOTT, J. G., GIBSON, J. B., ANDERSON, P. R., KNIBB, W. R., ANDERSON, D. G., and CHAMBER, G. K. (1982): Alcohol dehydrogenase dines in Drosophila melanogaster on different continents. - Evolution, 36 (1): 86-96. O'BRIEN, S. J. (1973): Comparative analysis of malate dehydrogenases of Drosophila melanogaster. Biochem. Genet., 10 (2): 191-205. O'BRIEN, S. J. and MACINTYRE, R. J. (1969): An analysis of gene-enzyme variability in natural populations of Drosophila melanogaster and D. simulans. - The American Naturalist, 103 (930): 97-113. PRAKASH, R. and GILL, K. S. (1980): Isozyme polymorphism in six Drosophila species. - Indian J. of Experimental Biol., 18: 219-221. SCHWARTZ, M. and SOFER, W. (1976): Alcohol dehydrogenase negative mutants in Drosophila: Defects at the structural locus? - Genetics, 83: 125-236. TRIANT APHYLLIDIS, CD., PANOURGIAS, J. N., SCOURAS, Z. G. and IOANNIDIS, G. C. (1980): A comparison of gene-enzyme variation between Drosophila melanogaster and Drosophila simulans. - Genetics, 51 (3): 227-231. VILAGELIOU, LI. and GONZÁLE Z-DUARTE, R. (1984): Alcohol dehydrogenase from Drosophila funebris and Drosophila immigrans: Molecular and evolutionary aspects. - Biochem. Genet., 22 (9/10): 797-815. Author's address: K. PECSENYE Zoological Institute Lajos Kossuth University H-4010 Debrecen Hungary