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THE MINIATURE COMPLEX IN DROSOPHILA MELANOGASTER

1954; Oxford University Press; Volume: 39; Issue: 1 Linguagem: Inglês

10.1093/genetics/39.1.45

1943-2631

Herman M. Slatis, David A Willermet,

Light effects on plants

CCORDING to BRIDGES and BREHME (1944), the miniature locus (m, A 1-36.1 ) was discovered in August, 1910, and the gene has frequently recurred spontaneously and as an induced mutant.Immediately adjacent to m is the similar mutant dusky ( d y ) , which has been placed at 36.2, although not on the basis of crossover data (STURTEVANT and TAN 1937).Almost no work has been done on these mutants in Drosophila melanogaster, and little light has been shed on the relations between them by comparative studies of other species in the genus.STURTEVANT and TAN (1937) also found no crossovers in D. pseudoobscuru.Reports for D. virilis ( CHINO 1936), D. ananussue (KIKKAWA 1938), and D. hydei (SPENCER 1949) show some crossover distance between the two sex-linked loci which are assumed to correspond to m and dy in these species, but in each case the relative positions have not been tested directly, but have been calculated by mapping with a third locus.Further testing of D. virilis (KOMAI and TAKAKU 1949) has resulted in the finding of 8 wild-type flies among 22,334, a number too large to be ascribed to back-mutation (apparently markers were not used to identify crossovers).It may be assumed that an equal number of m d y flies occurred but were not recognized, giving a crossover value of about .07%.The small size of both m and d y wings is produced in an embryologically similar manner by decreasing the size of the cells (DORZHANSKY 1929; WADD- INGTON 1940).Both also cause a darkening of the wings, and there is a distinct change in the character of the wing epithelium such that moderately large winged flies like dusky may most readily be distinguished from wild type by their failure to reflect light in the same way that the wild type does.As this paper will show that there is a relationship between m and dy, these loci will be referred to as the " miniature complex.'' MATERIALS AND METHODSThe miniature complex alleles used in this study were m, m2259-4, mD, and dy.The m and dy alleles are of unknown origin, but may be presumed to be the standard mutants known by these designations, and therefore are of spontaneous origin.The m259-4 allele is an X-ray induced deficiency discovered by DEMEREC.It has been stated to be deficient for m but not d y .The nzD allele was provisionally reported by SLATIS ( 1949).The following description of this allele may be considered to be definitive.