Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Maternal age,development time, position effect variegation in Drosophila melanogaster | Génét. Sél. Evol. 1985 17 1 171-178 Note Maternal age development time position effect variegation in Drosophila melanogaster A. MILLS and I. HARTMANN-GOLDSTEIN . Station de Recherches avicoles Centre de Recherches de Tours Nouzilly F 37380 Monnaie Department of Genetics. University of Sheffield Western Bank Sheffield Slữ 2TN Great Britain Summary In Drosophila expression of position-effect variegation is enhanced by culturing flies at low temperatures. It is demonstrated that this effect may not be solely temperature dependent. Maternal age influences offspring development times. Futhermore at a given temperature the longer a fly takes to develop the more likely is it to exhibit position-effect variegation. Key words Maternal age development time Drosophila position-effect. Resume Age maternel durée de développement et effet de position type variegation chez Drosophila melanogaster Chez la Drosophile 1 expression de la diversite de 1 effet position est favorisee lorsque les mouches se développent sous des temperatures basses. Il a été démontré que cet effet n est pas uniquement dependant de la temperature. L age maternel influence la durée de développement des descendants. De plus pour une temperature donnée il semble que plus la durée de développement est longue plus 1 expression de l effet position est diversifiee. Mots clés Age maternel durée de développement Drosophile effet position. I. Introduction In Drosophila sp. the transposition of genes which accompanies chromosome translocations sometimes results in changes in gene action which are expressed as mutant phenotypes Spofford 1976 . Such phenomena are known as position-effects 172 A. MILLS I. HARTMANN-GOLDSTEIN Sturtevant 1925 . Position-effects are of two types Spofford 1976 . In one type the change in gene action is somatically stable and is expressed in all cells. In the other type the change in gene action is subject to wide and frequent statistical fluctuation in homogenous cells. In certain .
