Genetics of larval urea tolerance in Drosophila melanogaster

Abstract

The genetic control of larval tolerance to urea, a nitrogenous waste-product occurring naturally in crowded Drosophila cultures, was investigated in a set of five laboratory populations of D. melanogaster that had been successfully subjected to selection for increased larval urea tolerance. Larva to adult survivorship and development time at three different levels of urea were assayed on the five selected populations, their five matched controls and a set of 10 F1 hybrid populations derived from reciprocal crosses between pairs of selected and control populations. As expected from the results of previous studies, the selected populations exhibited greater larval tolerance to the toxic effects of urea, relative to their controls. Comparison of the hybrid and parental populations with respect to both survivorship and development time indicated that the genetic control of urea tolerance in the selected populations is largely dominant, and has a significant X-linked component. The data also suggested that females from the selected populations exercise a nongenetic maternal effect on the development time of their progeny, regardless of urea level.

Larval pupation site preference on fruit in different species of Drosophila

“…As the larvae sense an odor, they turn around and move towards the odor-causing substance, and crawling speed increases with concentration of the odorant (Hussaini et al . , 1985Joshi et al . Biotic residues are known to affect larval survival, development and female fecundity (Budnic & Brncic 1974, 1976Botella et al .…”

PHYSIOLOGICAL MECHANISMS OF EVOLVED DESICCATION RESISTANCE IN DROSOPHILA MELANOGASTER

“…Numerous researchers have shown that organisms respond to selection for increased resistance to environmental stresses, e.g. temperature (Bennett et al 1990;Huey et al 1991;Lenski and Bennett, 1993), starvation and urea (Gupta et al 1995;Joshi et al 1996). However, the genetic or physiological basis of evolved stress resistance is frequently unclear.…”

The effect of urea exposure on isoaspartyl content and protein l-isoaspartate methyltransferase activity in Drosophila melanogaster

“…These flies have been reared since 1980 on banana medium (normal food), under a 14-day generation cycle, at 25°C, with constant illumination. A urea-selected (MX) population was derived from each B population by providing larvae with banana medium containing urea (urea food) [10]. Adults were maintained in population cages with normal food, so that only the larvae were exposed to urea.…”

“…The experimental generation consisted of four groups, each replicated fivefold: control populations reared on normal and 300 mM urea food, and urea-selected populations reared on normal and 300 mM urea food. Control populations reared on urea food develop through the larval stages, albeit more slowly than on normal food [10], but suffer nearly complete mortality during pupation [21]. All measurements were done on third-instar wandering larvae, the stage just prior to pupation.…”

“…Resistance to urea's toxic effects can be achieved in the laboratory by selectively breeding urea-tolerant individuals. Mueller and colleagues subjected populations of the fruit fly, Drosophila melanogaster, to increasing levels of dietary urea for 25 generations [10]. In the larval stages, these populations live in and consume media containing 300 mM urea, which causes nearly complete mortality in unselected D. melanogaster.…”