1. In your lab notebook, answer these questions in complete sentences. What is a genotype? What is a phenotype?

3. RR

4. DdRr

6. An Intro to One of the Most Important Organism in Genetics History (second to E. coli )

9.  Breeds quickly  Easy to take care of  Can be handled easily  Shows clear phenotypes

10.  By pairing males and females of selected phenotypes, genotypes can be determined.  Genes can be mapped!

11.  Thomas Hunt Morgan described 61 mutations in his 1925 book, The Genetics of Drosophila.  48,981 articles about fruit flies, since 1905  Genetics, biochemistry, cell biology, developmental biology, evolutionary biology, ecology, zoology, toxicology, neuroscience Source: Michan et al. (2010)

12.  Alzheimer’s disease, drug effects, metabolism, radiation effects  Most mutations produce weaknesses as observed in the lab, in such ways as body morphology, shortened life span, sterility, or death.  Homeobox: master control genes that control the body plan; humans and flies have a similar code for determining front and back, up and down

13.  Some Drosophila genes have homologs (corresponding genes with similar structure and fuctions), in other animals, even vertebrates.  Some vertebrate genes when introduced into flies, do the job of the homologous fly gene.  It seems that there are more similarities among organisms than there are differences: universality.

14.  Wild type: the phenotypes typical of wild flies in the Northeastern U.S.  Mutant: any fly that isn’t wild type  Mutation: a difference in the allele of wild type

15. 4 homologous pairs of chromosomes:  2 pairs of large autosomes (non-sex chromosomes)  1 pair of very small autosomes  1 pair of sex chromosomes. Females normally have two X chromosomes; males have one X and one tiny Y chromosome.

16.  + = wild type  v = vestigial  +/+ would be homozygous wild type  v/v would be homozygous vestigial  +/v would be heterozygous

21.  Now we can set up a cross. We'll start with wingless flies. Apterous (ap) is a recessive trait that results in flies with no wings. We will start by crossing a wingless female fly with a wild type male: ap/ap x +/+

22.  P = parental generation, the parent flies we mate in the cross. F1 = the first generation of offspring F2 = the second generation. There can be an F3, F4, etc. Progeny = offspring, the children of the parents.

24.  P: ap / ap x + / +  How do we determine what the progeny will be?