Genetic architecture of developmental time in Drosophila melanogaster

MENSCH, J; LAVAGNINO, N; CARREIRA, V.; FANARA, JJ

Guaruja, Brasil

Congreso; 2nd International Meeting of the Latin American Society of Developmental Biology; 2005

Organisms with metamorphosis are characterized by drastic morphological, physiological and behavioural changes during their ontogeny. In this sense, the time to reach the reproductive age is a complex trait with great adaptive relevance known as developmental time. In models organisms, ecological aspects of this trait has been deeply analyzed, but not much efforts have been made to study the genetic architecture of this adaptive character. The aim of this work is to study the basis and genetic architecture of developmental time in Drosophila melanogaster. In this sense, a P-element insertional mutagenesis methodology was employed for genetic screening. We screened 200 independent co-isogenic P-elements insertion lines to identify candidate genes affecting developmental time. The screening consists in finding phenotypic differences between P-elements lines and a co-isogenic control line P-element insertion free. In order to identify the mutated genes, nucleotide sequences flanking the P-element insertion were employed as in silico probes to search homologous regions in the D. melanogaster genome. The results show a highly significant mutational variance among single P-element insertion lines for developmental time. In addition we detected a significant line by sex interaction suggesting that the expression of the gene inserted depends on the sex analyzed. In most of the lines that showed a highly significant difference in developmental time as compared to control line, we performed a second phenotypic assessment to confirm our first screening. In this case, five of the retested lines were confirmed, indicating that those genes are involved in this adaptive trait. Particularly, the P-element insertion line affecting the expression of CG 18265 gene prolonged more than two days developmental time in both sexes. Surprisingly, this line does not showed significant differences as compared to the control under different temperature conditions (25º C and 17º) suggesting a significant genotype by environment interaction. Based on this result, we discuss the relevance of genetics as well the environmental components in the phenotypic model of this adaptive trait.