Session 1: The Life Cycle of Drosophila melanogaster PDF

GENETICS (LABORATORY) ADRIAN C. QUIAMBAO INSTRUCTOR  Culturing and Breeding Drosophila melanogaster Getting to know the Fruit Fly Drosophila melanogaster Drosophila melanogaster scientific classification  Why is Drosophila melanogaster a popular genetic model? Why is Drosophila mel...

GENETICS (LABORATORY) ADRIAN C. QUIAMBAO INSTRUCTOR  Culturing and Breeding Drosophila melanogaster Getting to know the Fruit Fly Drosophila melanogaster Drosophila melanogaster scientific classification  Why is Drosophila melanogaster a popular genetic model? Why is Drosophila melanogaster a popular genetic model? Short lifespan Minimal culturing requirements Genetic manipulation Anatomical features  SHORT LIFESPAN Allows a large quantity of flies to be produced within a short period. An embryo emerges within 24 hours of egg fertilization. This embryo then goes through three different larval stages eventually maturing into an adult Drosophila. Development of an adult fly only takes 10 days from fertilization. The female fly can produce up to 1500 eggs in its CULTURE REQUIREMENT Due to their small size and minimal requirements, many Drosophila can be raised and tested within a small laboratory which does not have access time, space or funding.  GENETIC MANIPULATION D.melanogaster only has four pairs of chromosomes compared to 23 pairs in humans. ANATOMICAL FEATURES Drosophila has anatomical features (such as wings and eyes) which allow for easy characterization. These genetic markers can be easily identified under a microscope.  The Life Cycle of Drosophila melanogaster Life Cycle of Drosophila melanogaster The embryo: Embryos are small, oval shaped, and have two filaments at one end. The larval stage: The larva look like worms. They use black mouth hooks to eat. Three larval stages. The pupal stage: A pupa undergoes four days of metamorphosis. They form a hard and dark pupal case. The adult stage: Adult flies have a head, thorax, abdomen, six legs, and two wings. They live a month Egg Laying in D. melanogaster  Larva to Pupa Stage With the onset of pupation, the worm- like larva Larvae are contracts mobile and a parchment- like pupa case hardens around the metamorpho How can you distinguish a male and a female Drosophila melanogaster? Male vs Female Drosophila melanogaster  Male vs Female Drosophila melanogaster Size of adult The female is larger than the male.  Male vs Female Drosophila melanogaster Size: The female abdomen curves to a point; the male abdomen is round  Male vs Female Drosophila melanogaster Markings: Alternating dark and light bands can be seen on the entire rear portion of the female; the last few segments of the male are fused.  Male vs Female Drosophila melanogaster Appearance of sex comb: On males there is a tiny tuft of hairs on the front legs.  Male vs Female Drosophila melanogaster External genitalia on abdomen: Located at the tip of the abdomen, the ovipositor of the female is pointed. The claspers of the male are darkly pigmented, arranged in circular form, and located just ventral to SUMMARY Female Male Female Fruit Fly This is a *female* fruit fly Notice the tiger-striped abdomen and the simple tag-like tip on the abdomen. Male Fruit Fly This is a mature male fruit fly. Mature males have a prominent black abdominal end. Males also have tiny “sex combs” on their front pair of legs. One male and one female Find their distinguishing features.  Phenotypes of Drosophila melanogaster  Phenotypes of Drosophila melanogaster  Phenotypes of Drosophila melanogaster Mutant Phenotypes  Breeding Method of Drosophila melanogaster Tools for culturing Drosophila