Isoenzymatic polymorphisms in urban populations of Drosophila willistoni Polimorfísmo isoenzímático en poblaciones urbanas de Drosophila willistoni

Natural populations of Drosophila willistoni collected both in urban sites and in the wild, as control, were analysed with respect to their isoenzyme polymorphisms in six loci of enzyme systems, through horizontal electrophoresis. The first pool of populations was collected and analysed during the years 1987 and 1988, and the other during 1992 and 1993, in comparable seasons. The level of enzymatic polymorphism first detected was smaller in comparison to that observed four years later, suggesting an increase of variability along the time elapsed since the first sampling of this species, in the city of Porto Alegre. Our findings are suggestive of an increasing adjustment of the species to this new environment<br>Poblaciones naturales de Drosophila willistoni recolectadas en lugares urbanos y silvestres, como control, fueron analizadas según su polimorfismo isoenzimático en seis loci de sistemas enzimáticos, mediante electroforesis horizontal. El primer grupo de poblaciones fue obtenido y estudiado en los años 1987 y 1988, mientras el segundo lo fue en los años 1992 y 1993, en períodos del año comparables. El nivel de polimorfismo enzimático detectado en el primer período fue pequeño en comparación con el detectado en el segundo grupo de muestras, obtenidas cuatro años después, sugiriendo un incremento de variabilidad temporal. Nuestros hallazgos sugieren un ajuste creciente de la especie a su nuevo ambient

Drosophila relics hobo and hobo-MITEs transposons as raw material for new regulatory networks

Abstract Hypermutable strains of Drosophila simulans have been studied for 20 years. Several mutants were isolated and characterized, some of which had phenotypes associated with alteration in development; for example, showing ectopic legs with eyes being expressed in place of antennae. The causal agent of this hypermutability is a non-autonomous hobo-related sequence (hoboVA). Around 100 mobilizable copies of this element are present in the D. simulans genome, and these are likely mobilized by the autonomous and canonical hobo element. We have shown that hoboVA has transcription factor binding sites for the developmental genes, hunchback and even-skipped, and that this transposon is expressed in embryos, following the patterns of these genes. We suggest that hobo and hobo-related elements can be material for the emergence of new regulatory networks