Control of Female Reproduction in Drosophila: Genetic Dissection Using Gynandromorphs

Abstract

The sexual behavior of Drosophila melanogaster gynandromorphs was studied to analyze the relationship between different steps in the female reproductive pathway. It was assumed that, in some gynandromorphs, certain female functions are missing because the corresponding control sites (foci) are either composed of male tissue or did not develop. A given gynandromorph can show elements of both male and female reproductive pathways. None of the steps of the female reproductive pathway appeared to be dependent on any other, in contrast to male behavior where, for example, following of females is a prerequisite for attempted copulation. By correlating each of the behaviors with the genotype of the cuticle, we confirmed previous findings that the focus for the female sex appeal is located in the abdomen, but receptivity to copulation is controlled by a site in the head. Many of the gynandromorphs did not lay eggs, presumably because either the focus controlling egg transfer from the ovaries to the uterus or the one controlling egg deposition was composed of male tissue. Many of the nonovipositing gynandromorphs laid eggs while dying or could be induced to deposit eggs after implantation of hormone-producing glands or topical application of a juvenile hormone analog. Some of the noninseminated gynandromorphs laid eggs at the rate characteristic for inseminated females, suggesting that an oviposition focus (mapping in the head region) suppresses oviposition in virgin females, but not in gynandromorphs whose focus is composed of male tissue. Some of the inseminated gynandromorphs oviposited eggs at a low rate, possibly because the focus responsible for detection of insemination could not function properly. Some of the inseminated gynandromorphs laid unfertilized eggs, revealing the importance of the focus controlling sperm release from the seminal receptacle. Foci controlling egg transfer, egg deposition and sperm release are located in the thorax, according to mosaic fate mapping results and studies on the reproductive behavior of decapitated females. The location of egg deposition in the culture vial seems to be controlled by a brain site. Sexual behavior in Drosophila does not depend on the presence (or absence) of the ovary or germ line.

1,6-Hexanediol Is Inducing Homologous Recombination by Releasing BLM from Assemblysomes in Drosophila melanogaster

“…For the somatic mutation and recombination test (SMART), two Drosophila strains were utilized: Bloomington Drosophila Stock Center's 2371 (flr/TM3,Ser) and 549 (mwh/mwh) stocks [19,38]. The mwh (multiple wing hairs) recessive allele, located on the left arm of chromosome 3, induces the growth of additional trichomes on the wing blades compared to the wild-type [19][20][21][22].…”

“…The mwh (multiple wing hairs) recessive allele, located on the left arm of chromosome 3, induces the growth of additional trichomes on the wing blades compared to the wild-type [19][20][21][22]. The Ser (Serrate) dominant marker produces a noticeable wing indentation, and the balancer chromosome TM3 inhibits HR during the experiment [19,20,27,38]. Marker heterozygous larvae were created by crossing the two strains in both directions.…”

“…The SMART wingspot test, largely adopted from [17][18][19]38], evaluates the mutagenic/ DNA-modifying capacity of various treatments in vivo. The method relies on somatic mutations manifested as mosaic spots in adult fruit fly wings.…”

“…The method relies on somatic mutations manifested as mosaic spots in adult fruit fly wings. The formula ( f = nm NC ; where "n" is the number of mosaic spots, "m" is the average size of the spots, "N" is the number of wings checked, and "C" is the number of cells comprising a wing blade (about 30,000)) helps infer mutational events in larval imaginal discs [19,21,38]. Larvae were treated, collected, and raised in test tubes until they developed pupae.…”

The timing of the sperm effect on female Drosophila melanogaster receptivity

“…Female D. melanogaster receptivity is controlled by sites in the brain (Bouletreau-Merle 1976: Szabad & Fajszi 1982Tompkins & Hall 1983). so stored sperm probably maintains the loss of female recepti\ ity through an interaction with the central nervous system (CNS).…”