THE PRODUCTION OF CHROMOSOME INTERCHANGES IN DROSOPHILA VIRILIS

The production of chromosome interchanges in Drosophila virilis.

ULLER'S original discovery that ionizing radiations are capable of 141 breaking the chromosome thread was based on investigations carried out with Drosophila melanogaster. But in spite of the numerous studies which have been undertaken using this animal, comparatively little progress has been made in the last twenty years in determining the precise manner in which these breaks are formed and th...

DNA-protein interactions in the Drosophila virilis mitochondrial chromosome.

The location of proteins on the mitochondrial DNA (mtDNA) of Drosophila virilis was investigated by Me3 psoralen photoreaction of mitochondria isolated from embryos. After photoreaction the mtDNA was purified and the pattern of DNA cross-linking was determined by electron microscopy of the DNA under totally denaturing conditions. The transcribed regions of the mtDNA molecule contained some uncr...

Chromosome Homologies in Two Sub-species of Drosophila Virilis.

Chromosome Segregation in Drosophila Virilis Males with Multiple Sex Chromosomes.

NE of the many puzzling aspects of chromosome mechanics is the process of 0 pairing of homologous chromosomes and their disjunction a t the first meiotic division. A genetic indication of the intimacy of pairing is the amount of exchange taking place between homologous chromosomes. Where more than two chromosomes share homologies, as in translocation heterozygotes, the correlation between excha...

Evolution of a distinct genomic domain in Drosophila: comparative analysis of the dot chromosome in Drosophila melanogaster and Drosophila virilis.

The distal arm of the fourth ("dot") chromosome of Drosophila melanogaster is unusual in that it exhibits an amalgamation of heterochromatic properties (e.g., dense packaging, late replication) and euchromatic properties (e.g., gene density similar to euchromatic domains, replication during polytenization). To examine the evolution of this unusual domain, we undertook a comparative study by gen...