È stato studiato il grado di polimorfismo elettroforetico di due geni, uno per l'alcooldeidrogenasi (ADH) e l'altro per l'$\alpha$-glicerofosfatodeidrogenasi ($\alpha$-GPDH), localizzati entrambi sul secondo cromosoma, in sette popolazioni naturali di Drosophila melanogaster raccolte in cantine o fuori di queste in due anni successivi. Dopo aver mantenuto la progenie delle sette popolazioni originarie come popolazioni di laboratorio (circa $10^{4}$ individui) per circa 25-30 generazioni, sono state misurate nuovamente le frequenze alleliche dei due loci in due delle sette popolazioni di laboratorio. I risultati ottenuti hanno permesso di valutare la ipotesi, avanzata da numerosi Autori, di un vantaggio selettivo a favore di individui portatori dell'allele $Adh^{4}$, a cui è associata un'attività enzimatica maggiore dell'allele $Adh^{6}$, e di interpretare i cambiamenti nelle frequenze geniche della ADH nelle due popolazioni di laboratorio come una conseguenza delle più grandi variazioni nelle frequenze geniche dell'$\alpha$-GPDH.
Referenze Bibliografiche
[1] R. K. SELANDER, S. Y. YANG, R. C. LEWONTIN and W. F. JOHNSON (1970) - Genetic variation in the horseshoe crab (Limulus polyphemus), a phylogenetic "relic", «Evolution», 24, 402.
[2] P. D. N. HEBERT (1974) - Enzyme variability in natural populations of Daphnia magna. II. Genotypic frequencies in permanent populations, «Genetics», 77, 323.
[3] F. J. AYALA, M. L. TRACEY, L. G. BARR, J. F. MCDONALD and S. PEREZ-SALAS (1974) - Genetic variation in natural populations of five Drosophila species and the hypothesis of the selective neutrality of protein polymorphisms, «Genetics», 77, 343.
[4] J. M. BURNS and F. M. JOHNSON (1971) - Esterase polymorphism in the butterfly Hemiargus isola: stability in a variable environment, «Proc. Nat. Acad. Sci.», 68, 34.
[5] E. K. TOMASZEWSKI, H. E. SCHAFFER and F.M. JOHNSON (1973) - Isozyme genotype-environment associations in natural populations of the Harvester ant, Pogonomyrmex badius, «Genetics», 75, 405.
[6] J. B. MITTON and R. K. KOEHN (1975) - Genetic organization and adaptive response of allozymes to ecological variables in Fundulus heteroclitus, «Genetics», 79, 97.
[7] C. WILLS and L. NICHOLS (1971) - Single gene heterosis in Drosophila revealed by inbreeding, «Nature», 233, 123.
[8] G. DE JONG, A. J. W. HOORN, G. E. W. THORIG and W. SCHARLOO (1972) - Frequencies of Amylase variants in Drosophila melanogaster, «Nature», 238, 453.
[9] D. A. BRISCOE, A. ROBERTSON and J. M. MALPICA (1975) - Dominance at Adh locus in response of adult Drosophila melanogaster to environmental alcohol, «Nature», 255, 148.
[10] A. M. TORRES (1976) - Dissociation-recombination of intergenic sunflower alcohol dehydrogenase isozymes and relative isozyme activities, «Biochem. Genet.», 14, 87.
[11] F. M. JOHNSON and C. DENNISTON (1964) - Genetic variations of alcohol dehydrogenase in Drosophila melanogaster, «Nature», 204, 906.
[12] M. SMITH, D. A. HOPKINSON and H. HARRIS (1971) - Development changes and polymorphism in human alcohol dehydrogenase, «Ann. Hum. Genet.», 34, 251.
[13] E. H. GRELL, K. B. JACOBSON and J. B. MURPHY (1965) - Alcohol dehydrogenase in Drosophila melanogaster: isozymes and genetic variants, «Science», 149, 80.
[14] C. L. VIGUE and F. M. JOHNSON (1973) - Isozyme variability in species of the genus Drosophila. IV. Frequency-property-environment relationships of allelic alcohol dehydrogenases in Drosophila melanogaster, «Biochem. Genet.», 9, 213.
[15] J. B. GIBSON (1970) - Enzyme flexibility in Drosophila melanogaster «Nature», 227, 959.
[16] T. H. DAY, P. C. HILLIER and B. CLARKE (1974) - Properties of genetically polymorphic isozymes of alcohol dehydrogenase in Drosophila melanogaster, «Biochem. Genet.», 11, 141.
[17] A. J. BIRLEY and B. W. BARNES (1973) - Genetical variation of enzyme activity in a population of Drosophila melanogaster. I. Extent of the variation for alcohol dehydrogenase activity, «Heredity», 31, 413.
[18] C. DELTOMBE-LIETAERT, M. LIBION-MANNAERT and A. ELENS (1974) - Ebony gene and selective value of ADH isozyme alleles, «D.I.S.», 51, 132.
[19] J. B. GIBSON and R. MIKLOVICH (1971) - Modes of variation in alcohol dehydrogenase in Drosophila melanogaster, «Experientia», 27, 99.
[20] R. D. WARD and P. D. N. HEBERT (1972) - Variability of alcohol dehydrogenase activity in natural population of Drosophila melanogaster, «Nature New Biol.», 236, 243.
[21] S. J. O'BRIEN and R. J. MACINTYRE (1972 b) - The $\alpha$-glycerophosphate in Drosophila melanogaster. II. Genetic aspects, «Genetics», 71, 127.
[22] S. J. O'BRIEN and R. J. MACINTYRE (1972 a) - The $\alpha$-glycerophosphate cycle in Droso phila melanogaster. I. Biochemical and developmental aspects, «Biochem. Genet.», 7, 141.
[23] G. C. BEWLEY, J. M. RAWLS and J. C. LUCCHESI (1974) - $\alpha$-Glycerophosphate dehydrogenase in Drosophila melanogaster: kinetic differences and development differentiation of the larval and adult isozymes, «J. Insect. Physiol.», 20, 153.
[24] S. MILLER, R. W. PEARCY and E. BERGER (1975) - Polymorphism at the $\alpha$-Glycerophosphate dehydrogenase locus in Drosophila melanogaster. I. Properties of adult allozymes, «Biochem. Genet.», 13, 175.
[25] J. C. LUCCHESI and J. M. RAWLS Jr. (1973) - Regulation of gene function: A comparison of enzyme activity levels in relation to gene dosage in diploids and triploids of Drosophila melanogaster, «Biochem. Genet.», 9, 41.
[26] F. LEIBENGUTH (1975) - Variants of $\alpha$-Glycerophosphate dehydrogenase in diploids and triploids of Drosophila melanogaster, «Biochem, Genet.», 13, 263.
[27] E. BERGER (1971) - A temporal survey of allelic variation in natural and laboratory populations of Drosophila melanogaster, «Genetics», 67, 121.
[28] F. M. JOHNSON and H. E. SCHAFFER (1973) - Isozyme variability in species of the genus Drosophila. VII. Genotype-environment relationships in populations of Drosophila melanogaster from the Eastern United States, «Biochem. Genet.», 10, 149.
Con il contributo del Ministero per i Beni e le Attività Culturali