Chinese name: Drosophila melanogaster Latin scientific name: Drosophila melanogaster alias: Drosophila melanogaster Megan realm: Animal kingdom: Arthropoda subclass: hexapod. Class: Insecta: Arachnida: Diptera: Trichopodidae: Drosophila: Drosophila species: Drosophila melanogaster. Distribution: Appearance characteristics, living habits, growth and reproduction, embryonic development, larval development, pupation, genetic research, mutants and appearance characteristics of temperate and tropical climate regions around the world. The female body length of Drosophila melanogaster is 2.5 mm, and the male is smaller than the female. Male abdomen has black spots, forelimbs have six combs, and females don't, which can be used to distinguish. Living habits of male and female Drosophila melanogaster larvae are mainly fed by microorganisms such as yeast and bacteria in rotten fruits, followed by sugary fruits. The growth and development of Drosophila melanogaster is greatly influenced by temperature. At the same time, the initial period and peak period of fruit fly in orchard should be determined according to the ripening time of cherry. Due to the influence of climate, environment and other factors, the annual occurrence time is different. Female flies can lay 400 eggs (eggs) with a size of 0.5 mm at a time, and the eggs are covered by chorion and yolk membrane. Its development speed is affected by environmental temperature. At 25℃, the larvae will hatch after 22 hours. Too high or too low temperature will affect the development speed. Adult female flies usually lay their eggs on rotten fruits or other fermented organic matter. After 22 hours of embryonic development, the fertilized egg and embryonic cuticle of Drosophila melanogaster were fertilized by egg cells, and after the fusion of sperm nuclei, the nuclei rapidly and continuously divided synchronously (mitosis). But these nuclei are on the same cell membrane, so it can be said that this is a multinucleated embryo, which is the so-called "syncytial blastoderm". After the seventh mitosis, these nuclei will dissociate under the cell membrane. During the ninth and tenth nuclear fission, eight to ten nuclei began to split by themselves. These cells become germ cells and are called polar cells. Two and a half hours after spawning, the cell membrane of syncytial blastoderm folds inward to wrap each nucleus, becoming a "cell blastoderm". At this point, the first monolayer epidermis of Drosophila embryo cells was formed. The nucleus also began to turn to asymmetric differentiation. Its differentiation direction is related to the position of cells in the embryo. The cleavage of the ventral extension axis of the fertilized egg marks the beginning of gastrulation, in which three germ layers will be formed: ventral cleavage forms mesoderm. The anterior segment of abdominal sulcus invaginates to form oral canal, and the posterior segment invaginates to form anal fossa, which is separated from the endoderm formed later. Embryonic outer layer cells, cells at the end of oral cavity and anal fossa invaginate to form ectoderm. With the extension of the embryo zone, the polar cells in the later stage began to divide into embryos. Organ differentiation has begun, and the phenomenon of segmentation can already be seen. About 7.5 hours after fertilization, the embryonic area began to shorten and ended with dorsal closure. 22 hours after fertilization, after a series of differentiation and development, the larvae will develop and take shape. The Lavae of Drosophila melanogaster molt for the first time after 24 hours of larval development, and continue to grow to the second and third larval development stages. Larvae can grow from a fertilized egg of half a millimeter to a normal size of 2.5 millimeters in a few days. It molts twice, so its larval development can be divided into three stages (L 1-L3). This is the fastest growing stage of fruit flies. In just three days, the body of fruit flies has increased by more than 200 times. Recent studies have found that this is caused by the estrogen-like receptor (ERR) gene involved in the regulation of glycolysis in Drosophila. Larvae like to pupate and gather in slightly hard places such as catheter walls and grape stalks. Stop crawling when you find the pupation position, and the body keeps shrinking and crawling at the pupation position. The degree of shrinkage decreases with the process of pupation, and finally the shape of pupa is formed. It took 1 ~ 2 h to stop crawling and pupae appeared. The newly formed pupa is light yellow, then the color gradually deepens, and it is dark brown before eclosion. At 25℃, pupation goes through three stages of larval development and five days of metamorphosis, and finally pupation (eclosion) becomes an adult (* * *). Pupa shell is translucent, yellow-brown, or dark yellow-brown, rectangular. A breathing tube extends from the front end of the pupa. The genetic study of Drosophila melanogaster was first described in 1830. For the first time, it was 190 1 year. William Ernest Castle, a zoologist and geneticist, tried to understand the results of multiple generations of inbreeding and hybridization from one generation. 19 10, Thomas Hunt Morgan began to cultivate Drosophila in the laboratory and made a systematic study on it. After that, many geneticists began to use Drosophila as research materials and gained a lot of genetic knowledge, including the distribution of genes in the Drosophila genome on chromosomes. Drosophila has only four pairs of chromosomes. They include a pair of sex chromosomes, usually called the first chromosome or X and Y chromosomes, and three pairs of autosomes. The latter is recorded as the second, third and fourth pairs of chromosomes. The fourth pair of chromosomes is very small and contains few genes. Drosophila is very suitable for research. A large number of fruit flies can be cultivated in a bottle, and the reproduction speed is fast. Martin buchs published his book.