On the Occurrence of Translocations and Autosomal Non-Disjunction in Drosophila melanogaster

Abstract

Recent findings on different plants indicate that the presence of extra chromosomes in an organism facilitates the occurrence of exchanges of non-homologous chromosomal parts. It seemed desirable to test if such exchanges occur also in heteroploid Drosophila melanogaster both from the point of the validity of the generalization of the findings as well as for the possibility of finding a method to obtain non-homologous exchanges in non-radiated flies. Triploid Drosophilae were chosen for this investigation. Translocations within one chromosomal pair as well as between non-homologous chromosomes were to be expected if the findings on plants would hold true for Drosophila. However, as a first part of the investigation, only the possibility of translocations between non-homologous chromosomes was tested.The outcome was fully negative: None of the more than 900 haploid gametes coming from triploid females contained a translocation between the first, second or third chromosomes (the fourth chromosome was-on account of its comparatively small size-expected to be of less importance than the others and its fate therefore not followed). The result can be explained as due to the fact that the frequency of translocations between nonhomologous chromosomes in triploid Drosophilae is very low. If one considers the fact, however, that the production of a haploid egg from triploid females, which contains the two non-homologous chromosomes that underwent a possible interchange, is only one of different possibilities during meiosis, the number of 900 gametes tested might still have been too low. Certainly the method used has proved to be of no value for obtaining translocations.A brief record of the data, which constitute not only the basis for the 36 PROC. N. A S.

A gap-free genome assembly of Chlamydomonas reinhardtii and detection of translocations induced by CRISPR-mediated mutagenesis

“…Screening recombinant progeny provided irrevocable evidence that recombination involved physical exchange of DNA. Comparable results were also observed in Drosophila by Stern (1934) . Many species of evening primrose carry multiple reciprocal translocations and form multi-chromosomal meiotic rings involving all 14 chromosomes ( Cleland, 1972 ).…”

Interchromosomal Effects of Inversions in Drosophila Melanogaster

“…Such a compensating system can be provided by triploid females, in which the proper kind of aneuploid gametes occurs with a predictable frequency. This method has been successfully used for investigations of autosomal non-disjunction or loss in males (STERN, 1934;PONTECORVO, 1942;FROST, 1961 a ) . But considering the interchromosomal effect of inversions on crossing-over it is of more interest to study what happens in the females.…”

A Feed-Forward Loop Coupling Extracellular BMP Transport and Morphogenesis in Drosophila Wing

“…A candidate for mediating PCV formation is Crossveinless-C (Cv-C), whose viable mutant allele displays a PCV-less phenotype [18]. Recently, cv-c was identified as RhoGAP88C required for a variety of embryo morphogenesis [19].…”