Flies

. Drosophila crosses Introduction: The common fruit fly, Drosophila melanogaster, is mainly used for genetic studies. Fruit flies are easily cultured and can reproduce in as little as two weeks at the proper temperature. (Book) The purpose of this experiment was to study the transfer of genes between homologous chromosomes by crossing over. During our experiment we studied three X-chromosome genes: white (w), miniature (m), and forked (f). To begin this experiment we started with four types of flies; sepia, dumpy, wild, and wmf (white, miniature, forked). We kept each type of fly in separate vials containing media. For the first two weeks we mated like genotypes to ensure that we had plenty of flies for the cross. Once we had a sufficient amount of each type of fly, we separated males from females in each genotype. This is an important step, because to ensure the cross works correctly you need to cross virgin females with males. In order to get virgin females you have to separate the parent flys from the eggs, and keep a careful eye on the eggs. After a week the eggs will become larva and about two weeks after they are layed the larva, now pupa will hatch. This is when time is of the essence. We had a 12 hour window
Results:

DUMPY X SEPIA CROSS GROUP: 1
Male
Female
Total
Dumpy

5
Sepia

25
Wild type

40
GROUP: 3
Male
Female
Total
Dumpy

18
Dumpy wings and sepia eyes

5
Sepia

26
Wild type

46
GROUP: 4
Male
Female
Total
Dumpy
3
3
6
Sepia
18
19
37
Wild type
23
21
44

Wild X WMF GROUP:1
Male
Female
Total
Wild

33
WMF

25
White

1
Miniature, forked

3
White, miniature

2
Forked

4
White Forked

3
Miniature

3
GROUP:3
Male
Female
Total
Wild

96
WMF

13
White

8
Miniature, forked

10
White, miniature

77
Forked

6
White Forked

4
Miniature

11