1. Journal

2. Chromosomal Theory of Inheritance: simply states that chromosomes are carriers of genetic information Chromosomal Theory of Inheritance: simply states that chromosomes are carriers of genetic information (Walter Sutton)

3. Human Chromosomes (Karyotype) Humans have 22 pairs of autosomes, 1 pair of sex chromosomes Fruit flies have 3 pairs of autosomes, 1 pair of sex chromosomes What is the sex of this person?

4. Female eggs = XX Male sperm = XY Possible offspring are shown in square: 50% male 50% female What happens when an allele is located on the X chromosome? Males only get ONE !

5. These are a few of the known alleles located on the X chromosome Disorders that are recessive are masked in females by the other X chromosome.

6. Sex Linked Genes Genes located on the X chromosome are inherited with that X.Genes located on the X chromosome are inherited with that X. When doing crosses you must include the sex chromosomes in your cross.When doing crosses you must include the sex chromosomes in your cross. Use superscript letters for the allele. Example: In fruit flies, eye color is a sex linked trait. Red is dominant to whit e.Use superscript letters for the allele. Example: In fruit flies, eye color is a sex linked trait. Red is dominant to whit e. Females Males X R X R X R Y X R X R X R Y X R X r X r Y X R X r X r Y X r X r FRUIT FLY CHROMOSOMES Drosophila melanogaster

7. Figure 12.6 Thomas Morgan used crosses with fruit flies. Why do you think he used them?

8. Figure 12.1 What is an autosome?

9. Show the cross between a white eyed male and a red eyed female: X r Y x X R X R Show the cross between a red eyed male and a white eyed female: Show the cross between a red eyed male and a white eyed female:

10. Figure 12.2

11. Human Sex Linked Disorders 1.Colorblindness 2.Muscular Dystrophy 3.Hemophilia 4.Fragile X Syndrome

12. COLORBLINDNESS

13. More Tests

14. Muscular Dystrophy characterized by the wasting away of muscles life expectancy: ~20 yrs females can be carriers for the disease, where they pass the disease to their sons only Show the cross of a female who is a carrier and a normal male:

15. Fragile X Syndrome caused by triplet repeats in a gene on the X chromosome causes mental retardation named because the X chromosome had an odd appearance - the tip of the chromosome seemed to be attached only by a small thread the number of repeats of the gene determines the severity of the disease

16. Figure 12Aa

17. Hemophilia also known as "bleeder's disease", blood does not clot properly disease was present in the royal family, starting with Queen Victoria Show the cross between a female with hemophilia and a normal man:

18. Pedigree Key Squares represent males Circles are used for females A horizontal line from male to female represents mates that have produced offspring The offspring are listed below their parents from oldest to youngest A fully shaded individual posses the trait being studied –If the condition being studied is a monogenic recessive condition (rr), then those shaded gray have the genotype rr –If the condition being studied is dominant condition (Rr or RR), then those that are unshaded have the genotype rr A line through a symbol indicated that the person is deceased

19. How to analyze a pedigree

20. Figure 12.5

21. Identify all of the CARRIERS