| In children, lead, even at very low levels, affects IQ, learning, perception, attention, activity level and language (Johnson 1998). The goal of this thesis is to establish Drosophila as a model to further our understanding of how lead affects the genetics of behavior.; Objective one was to establish a range of relevant lead exposure doses for this model system by determining lead burden and localization throughout the life cycle: in wandering 3rd instar larvae, in pupal cases, in newly eclosed adults, in older adults, in various tissues of wandering 3rd instar larvae, and in head, thorax and abdomen of adults. At all stages of life, Drosophila sequester most of the ingested lead in the gut. Lead burdens in this study are comparable to those known to cause cognitive defects in children.; Objective two was to examine lead as a selection pressure and to examine the nature and kinds of genes involved in lead-dependent effects by partitioning the genetic variance of copulation latency. Lead affects copulation success, copulation latency and the amount of additive genetic variation present for the trait, allowing selection to act within a leaded environment.; Objective three was to examine larval locomotion, identifying the amount of variation present in the response to lead and the major chromosomes responsible for lead-dependent differences using five chromosome substitution lines and two lead doses. Results indicate that variation in chromosomes 2 and 3 affects lead-dependent differences in locomotion of wandering 3rd instar larvae.; The studies described in this thesis demonstrate that Drosophila is an excellent model system for studying the behavioral genetics of lead toxicology. Characteristics which illustrate this are: (1) speed and ease of culture, allowing for large sample sizes and replication; (2) sensitivity at relevant doses; (3) similar responses as other models and children; (4) vast knowledge of genetic basis of several behaviors, allowing for the discrimination of lead's genetic effects. |
