Study On The Influence Mechanism Of Environmental Factors On Drosophila Population Differentiation

Mating selection is thought to be an early event in species formation.In this experiment,Drosophila melanogaster was cultured in corn flour medium(CMA)and molasses medium(CMY)in two different food environments.By monitoring the mating selectivity between Drosophila CMY offspring and CMA progeny populations,the metabolic ability of intestinal microbes to various organic compounds and the composition of dominant bacteria in the intestinal tract of Drosophila melanogaster were analyzed.The effects of physical isolation and food selection on mating selectivity of Drosophila melanogaster were investigated from different angles.This work is based on the environment-Molecular(enzymes,genes,intestinal microbes)-individual-population(mating behavior)levels,to study the effects of different media components on mating behavior of organisms and their populations.Explore the process of fruit fly selection to mate to form new species and the factors that influence this process.The research results show that:(1)In the experiment system,after 9 generations of different food culture,the reproductive isolation of CMY fruit fly and CMA fruit fly strain was constructed,which produced a clear and visible difference in reproductive selectivity,and this difference can be maintained in the future generations.(2)The carbon source utilization ability of intestinal bacteria of CMA Drosophila and CMY Drosophila was determined by using Biolog ECO culture plate.It was found that the number of carbon sources increased with the increase of culture generations.The metabolic ability of intestinal bacteria of Drosophila melanogaster to carbon source showed significant changes in molasses culture:compared with CMA Drosophila melanogaster,the enteric bacteria of CMY in each generation were compared withthose of CMA fruit fly,such as p-phenylethylamine and cellobiose.The metabolic ability of itaconic acid,?-butanone acid,?-hydroxybutyric acid,4-hydroxybenzoic acid and 2-hydroxybenzoic acid were enhanced in varying degrees.(3)The intestinal dominant metabolic bacteria of Drosophila CMA and Drosophila CMY were identified by Biolog GNIII culture plate.It was found that the dominant metabolizing bacteria were Lactobacillus plantarum in the intestinal tract of Drosophila CMA and Fusarium oxysporum in the intestinal tract of CMA Drosophila melanogaster.This indicates that food has a significant effect on intestinal bacteria of Drosophila melanogaster.(4)The second generation gene sequencing technique was used to sequence the whole gene sequence of CMA Drosophila and all generations of CMY Drosophila,which contained the regulatory region of the gene.Under physical isolation and food selection pressure,the regulatory region of EST-6 Ejaculatory duct tissue expression in Drosophila melanogaster has the same regulatory region as Gen Bank: AAA28517.1 gene Est-6,while CMY Drosophila has Ejaculatory duct of Est-6 gene.There were two inserted sequences in the regulatory region of tissue expression.Because the expression level of EST-6 in Drosophila Ejaculatory duct affected the mating behavior of Drosophila melanogaster,the insertion sequence was closely related to the significant change of mating selectivity between CMY and CMA.In conclusion,under the condition of physical isolation,the selection pressure of food not only affects the metabolism ability of intestinal bacteria to carbon source,but also affects the dominant intestinal bacteria species and gene stability of Drosophila.A further detailed study of the temporal relationship between the food pressure of Drosophila and the changes of the above factors will be helpful to further explore and clarify the key molecular events and the material basis of species evolution at a deeper level.