QUANTITAVIVE TRAIT LOCI FOR ADAPTATION TO THERMAL STRESS AND ACCLIMATION IN Drosophila melanogaster

SAMBUCETTI PD,; ARIAS L; A.C. SCANNAPIECO; F.M. NORRY

Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires

Otro; I Reunión de Biología Evolutiva del Cono Sur; 2009

Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires

st1:*{behavior:url(#ieooui) } <!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-US; mso-fareast-language:EN-US;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> The thermotolerance of a species is important for its adaptation under climatic conditions of global warming. Every living organism can cope with variable levels of thermal stress because of both basal and induced levels of thermotolerance. Induced thermotolerance is the increase in thermal resistance by pre-exposure to thermal stress. We used Drosophila melanogaster as a model organism to search for QTL affecting thermotolerance in both pre-adult and adult stages of the life cycle. This model insect was successful in colonizing wide geographic areas from tropical to temperate climates on most continents. We crossed flies derived from Jutland (Denmark) and Australia that dramatically differed for thermal resistance to set up RIL lines for QTL mapping heat-shock survival. We found major QTL for basal thermotolerance in adults only. We found a QTL in the middle of chromosome 2. In larvae we found QTL on the two major autosomes but only for acclimation (the ratio between induced and basal resistance), with no colocalization for thermotolerance QTL in adult insects. This result suggests that the genetic basis for thermotolerance may partly be different between life cycle stages.