Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh Original cung cấp cho các bạn kiến thức về sinh học đề tài:Phenotypic plasticity of body pigmentation in Drosophila: Genetic analysis by interspecific crosses of the tolerance of Drosophila sechellia to major aliphatic acids of its host plant. | Genet Sei Evol 1997 29 511-522 Elsevier Inra 511 Original article Genetic analysis by interspecific crosses of the tolerance of Drosophila sechellia to major aliphatic acids of its host plant M Amlou E Pla B Moreteau JR David Laboratoire populations génétique et evolution Centre national de la recherche scientifique 91198 Gif-sur-Yvette cedex France Received 3 March 1997 accepted 11 July 1997 Summary - Toxicity of hexanoic and octanoic acid ie the two major aliphatic acids found in ripe fruits of Morinda citrifolia was measured on adult flies of Drosophila sechellia D simulans Fl hybrids and backcrosses. With both acids tolerance was much higher in D sechellia than in D simulans while Fl and backcross progeny exhibited intermediate characteristics. Tolerance to these two acids in D sechellia appears to be a major mechanism for understanding the ecological specialization of that species to the toxic morinda. Significant differences in tolerance were found between sexes especially in Fl hybrids. The role of X-linked tolerance genes was however not obvious from the backcross generation and most of the interspecific difference seems to be autosomal and polygenic. Attempts were made to introgress the tolerance of D sechellia into D simulans by selecting with either morinda fruit or pure octanoic acid. Both techniques proved to be unsuccessful. Introgressed genotypes progressively returned to the apparently pure D simulans phenotype and tolerance regressed to the low value typical of that species. This barrier against introgression seems quite similar to the barrier observed in hybrid zones of various animal species. ecological specialization hexanoic acid octanoic acid interspecific hybrids barrier to introgression Resume Analyse génétique par croisement interspecifique de la tolerance de Drosophila sechellia aux deux principaux acides aliphatiques de sa plante hôte. La toxicité de I acide hexanoỉque et de I acide octanoi que deux acides aliphatiques majori-taires dans
