Subject(s)
Chromosomes , Diptera , Genes , Alleles , Animals , Base Sequence , Chromatin , DNA , Gene Frequency , Genetic Code , RNA/biosynthesis , RNA, Messenger , Salivary Glands , Transcription, Genetic , Tritium , Uridine/metabolismSubject(s)
Chromosomes , DNA/analysis , Drosophila , Animals , Chromosome Aberrations , Heterochromatin , Heterozygote , Microscopy, Electron , Salivary GlandsABSTRACT
From a consideration of genetic and chromosomal alterations which affect the banding pattern of a specific salivary chromosome region, it is concluded that (1) a regulator locus, sal, is closely linked with the region in question but separated from it spatially by a few bands; (2) either mutation of the sal locus or transfer of the region to a heterochromatic region affects the banding pattern similarly; and (3) the change probably consists of a compaction of DNA and a concomitant inactivation of genetic loci.
Subject(s)
Chromosomes , Drosophila , Alleles , Animals , Chromosome Aberrations , Genes, Regulator , GenotypeABSTRACT
In the mutant sal the banding pattern at the tip of chromosome 3 is changed. Certain bands are compacted instead of being partially puffed. In sal(+)/sal heterozygotes, when the chromosome tips are paired they both show the sal(+) pattern or are intermediate; but when unpaired, each shows the pattern characteristic of its own genotype.
Subject(s)
Chromosomes , Drosophila , Salivary Glands/cytology , Animals , Heterozygote , Homozygote , LarvaABSTRACT
An allele of the bobbed locus (bobbed bristle) behaved in crosses with other bobbed alleles as a weak isoallele to which extreme bobbed alleles were dominant. The results are consistent with the hypothesis that the bobbed locus contains multiple cistrons, some threshold number of which are needed to produce ribosomal RNA and the normal phenotype.
