How Drosophila change their combs: the Hox gene Sex combs reduced and sex comb variation among Sophophora species.

Identification of the events responsible for rapid morphological variation during evolution can help understand how developmental processes are changed by genetic modifications and thus produce diverse body features and shapes. Sex combs, a sexually dimorphic structure, show considerable variation in morphology and numbers among males from related species of Sophophora, a subgenus of Drosophila. To address which evolutionary changes in developmental processes underlie this diversity, we first analyzed the genetic network that controls morphogenesis of a single sex comb in the model D.

Getting new bronchodilator compounds from molecular topology.

Molecular topology has been used to select new lead bronchodilator compounds. The main advantage of this method, as compared to others frequently used, is that it does not require a previous explicit knowledge of the mechanism of action (MOA) of the compounds analyzed. A large database (12,000 chemicals) has been examined in this study to find less than 5% compounds with bronchodilator activity.

Differential requirements for the neurogenic gene almondex during Drosophila melanogaster development.

During early development, the neurogenic genes of Drosophila melanogaster are involved in the control of cell fates in the neurectoderm; almondex (amx) belongs to this category of genes. We have identified the amx locus and rescued the amx embryonic neurogenic phenotype with a 1.5 kb DNA fragment.

Regulation of larval hematopoiesis in Drosophila melanogaster: a role for the multi sex combs gene.

Drosophila larval hematopoietic organs produce circulating hemocytes that ensure the cellular host defense by recognizing and neutralizing non-self or noxious objects through phagocytosis or encapsulation and melanization. Hematopoietic lineage specification as well as blood cell proliferation and differentiation are tightly controlled. Mutations in genes that regulate lymph gland cell proliferation and hemocyte numbers in the body cavity cause hematopoietic organ overgrowth and hemocyte overproliferation.

The multi sex combs gene of Drosophila melanogaster is required for proliferation of the germline.

We present a genetic analysis showing that the Drosophila melanogaster gene multi sex combs (mxc; Santamaria and Randsholt 1995) is needed for proliferation of the germline. Fertility is the feature most easily affected by weak hypomorphic mutations of this very pleiotropic locus. Pole cell formation and early steps of gonadogenesis conform to the wild-type in embryos devoid of zygotic mxc product.

Pattern triplications following genetic ablation on the wing ofDrosophila : Effect of eliminating thepolyhomeotic gene.

The effects ofpolyhomeotic (ph) mutants in imaginal cells have been studied in a clonal analysis. Clones of cells, homozygous forph, sort-out after a few divisions, probably as a consequence of modified cell affinities. The dorso-ventral margin of the wing has special characteristics that retard this phenomenon.

Maternal and zygotic requirement for thepolyhomeotic complex genetic locus inDrosophila.

The complex genetic locuspolyhomeotic (ph) is a member of thePolycomb (Pc)-group of genes and as such is required for the normal expression of ANT-C and BX-C genes. It also has probably other functions since amorphicph alleles display a cell death phenotype in the ventral epidermis of 12-h-old embryos. Here it is shown that lethal alleles ofph (amorph and strong hypomorph) show transformation of most of their segments towards AB8.

On the causes of sterility in some interspecific hybrids from theMelanogaster subgroup ofDrosophila.

The females produced in the crossesD. melanogaster×D. simulans andD.

Developmental analysis of two wing scalloping mutantsct andBx ofDrosophila melanogaster.

The mutantscut (ct) andBeadex of Jollos (Bx ) show nicks in the wing margins as well as other malformations in different regions of the body. Clonal analysis of the wing disk's development in these mutants indicates that massive cell loss occurs during the third larval instar. Morphogenetic mosaics, originating from mitotic recombination, reveal a non-autonomous behaviour of both mutant and wild-type cells.