Drosophila was first described in 1830. 190 1 was taken as the experimental research object for the first time in, and the experimenter was the zoologist and geneticist William Ernst Custer. By studying the species of Drosophila, he tried to understand the results of multiple generations of inbreeding and hybridization from one of them. 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 study Drosophila melanogaster with Drosophila melanogaster, and gained a lot of genetic knowledge, including the distribution of genes in the genome of Drosophila melanogaster on chromosomes.
Appearance characteristics:
Small size, 3 ~ 4 mm in length. It is difficult to identify similar species, and its main feature is its huge red compound eye.
Ecological habits:
Drosophila insects are also common in home environment because they are small and easy to pass through sand windows. As long as a lot of red-eye flies are found in the trash can or beside the fruit that has been placed for a long time, it is a fruit fly; Drosophila larvae are used to breeding in garbage dumps or rotten fruits.
describe
Drosophila melanogaster is a fly native to tropical or subtropical regions. Like human beings, they are distributed all over the world and spend the winter on earth. The female is 2.5 mm long and the male is smaller. Males have dark hind limbs which can be distinguished from females.
Female flies can lay 400 eggs with a size of 0.5 mm at a time. They are covered by chorion and yolk membrane. Its development speed is affected by environmental temperature. At 25℃, after 22 hours, the larvae will break out of their shells and eat immediately. Because the mother will put them on rotten fruits or other fermented organic matter, their primary food source is the microorganisms of rotten fruits, such as yeast and bacteria, followed by sugary fruits. Larvae will molt for the first time after 24 hours and continue to grow to the second stage of larval development. Larval development has three stages, the pupal stage is 4 days, and it develops into an adult at 25℃ 1 day.
Transgenic Drosophila was born: it can be remotely controlled by laser irradiation.
Remote control is no longer the patent of electronic products. Scientists have newly cultivated a transgenic fruit fly, which can remotely control their behavior through laser irradiation, and make lazy fruit flies move and start crawling, jumping or flying away.
The paper was published in the latest issue of Cell magazine. Although the remote control of this fruit fly is not as convenient as driving a remote control car, the related methods are of great significance for studying the nerves and behaviors of animals.
In the past, when scientists studied the neural basis of animal behavior, they generally used methods such as stimulating nerves with electrodes. But these methods are invasive, which may hinder the action of animals or even paralyze them, and it is impossible for electrodes to touch every neuron in the whole nervous system.
Neurobiologists at Yale University School of Medicine implanted rat genes into fruit flies, which encoded an ion channel protein. In the presence of biological energy molecule ATP in the environment, ion channels allow charged particles to pass through the cell membrane, thus transmitting electric pulses.
Subsequently, the researchers injected the fruit fly with ATP molecules, which were inactive because they were wrapped by another molecule. Irradiating Drosophila melanogaster with ultraviolet laser can free ATP molecules from bondage, start ion channels and stimulate the nerves of Drosophila melanogaster with electrical signals.
Experiments show that if ion channel proteins are expressed in dopaminergic neurons that control the crawling of Drosophila melanogaster, the originally lazy Drosophila melanogaster will become too active under laser irradiation. If ion channels are expressed in the great nerves that control the flight response of fruit flies, lasers can make fruit flies jump around and flutter their wings and fly away.
Researchers say that this technology can be used to study many other behaviors of organisms, such as courtship, mating and eating.
Drosophila can be divided into white eyes and red eyes. White eyes are the result of gene mutation and recessive inheritance on X chromosome. Because it has only four pairs of chromosomes, it is convenient for experimental observation and is often used to study sex-linked inheritance. American biologist Morgan used this trait to study the law of gene linkage and exchange.