1. Basics of Drosophilia Genetics

2. Basic Fly Anatomy

4. Male and Female Fly

5. Fly Morphology

6. Female
Male

7. Defining Important Terms
Karyotype
Sex Chromosome XX, XY
Gene
Locus
Allele
Phenotype
Genotype

8. Wild Type
Mutant Type
Homozygous
Heterozygous
Hemizygous
Dominant
Recessive

9. Karyotype

10. Meiosis Overview

11. Meiosis I

12. Meiosis II

14. Monohybrid Cross

15. Female Fly and Virgins

17. The Naming Game
The best way to study a gene is to mutate it and see what happens when the gene’s function is lost. As a result, genes are usually named after the phenotype caused by the mutation.
The white gene, which codes for eye color. Flies with a normal version of the white gene (usually written as w+ ) actually have red eyes, while flies with a mutation in the white gene ( w– ) have white eyes.
The name and symbol are capitalized if the phenotype of the mutant allele for which the gene was named is dominant to a wild-type allele.

18. Mutants to Identify

19. Normal Wildtypes
These normal fruit flies, or "wildtypes," have black-and-tan striped bodies. Compare them with the other fruit flies here.

20. Yellow Flies Notice that these flies are yellower than normal flies
Yellow Flies Notice that these flies are yellower than normal flies. They have a defect in their "yellow gene," which is on the X chromosome. Since the yellow gene is needed for producing a fly's normal black pigment, yellow mutant flies cannot produce this pigment. y

21. Ebony Flies
Notice that these flies have a dark, almost black, body. They carry a defect in their "ebony gene," on the third chromosome. Normally, the ebony gene is responsible for building up the tan-colored pigments in the normal fruit fly. If the ebony gene is defective, the black pigments accumulate all over the body. e

22. White Flies
These flies have white eyes. They have a defect in their "white" gene, like orange-eyed flies. But in these flies, the white gene is totally defective: it produces no red pigment at all.  w

23. Curly Wing

24. Lobed Eyes v Normal L

25. Stubble Sb

26. Examples of ‘Funny’ Gene Names
Cheapdate– mutants have decreased resistance to the effects of alcohol
Hangover– mutants can’t develop a tolerance for alcohol
Dunce– mutants have learning deficits
Tinman– This gene regulates the development of a heart, so flies with a mutation in this gene can’t grow a heart. Named after the character in Wizard of Oz
Ken and Barbie – mutants do not develop external genitals
Swiss cheese – mutants have holes in their brain
I’m not dead yet – mutants live twice as long as normal flies, a reference to Monty Python and the Holy Grail
Groucho Marx – mutants develop an excess of facial bristles
Out Cold – mutants lose coordination at cold temperatures
Clumsy – mutants have trouble walking