Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Phenotypic and genotypic differentiation in cage populations of Drosophila melanogaster development, thorax size and weight | Génét. Sét. Evol. 1987 19 2 155-170 Phenotypic and genotypic differentiation in cage populations of Drosophila melanogaster I. Duration of development thorax size and weight . LINTS and M. BOURGOIS Laboratoừe de Génétique Université de Louvain Place Croix du Sud 2 B-l 348 Louvain-la-Neuve Belgium Summary Oregon-R a wild type laboratory stock of Drosophila melanogaster was divided into 3 subpopulations which were submitted to different environmental temperatures. During 6 years duration of development thorax size and male wet weight were measured several times in the 3 subpopulations. A genetic divergence between subpopulations was already observed 36 weeks after initiatioiLThat series of experiments confirms the results obtained with Vetukhiv s subpopulations of Drosophila pseudoobscura. Furthermore it shows that a genetic differentiation between subpoPulations .may. e. n ch been suspected even in subpopulations initiated contrary to the Vetukhivs subpopulations from a population with a narrow genetic base. Different hypotheses which may explain the origin of the genetic variability present in subpopulations derived from a laboratory stock maintained in a constant environment during more than 15 years are discussed. Key words Evolution genetic divergence development Drosophila melanogaster cage populations genetic variability. Resume Differentiations phénotypique et genotypique dans des cages à population de Drosophila melanogaster I. Durée de développement taille thoracique et poids frats Chez Drosophila melanogaster 3 sous-populations ont étệ créées à partir de la souche de laboratoire Oregon-R. Ces 3 sous-populations maintenues à 3 temperatures differentes ont été observées à plusieurs reprises durant 6 ans. Les caractères mesurés étaient la durée ùe développe-ment la tailie thoracique et le poids frais. Déjà après 36 semaines une différenciation génétique entre sous-populations a été observée. Ces observations confirment les résultats