1. d. Multiple Alleles – Instead of having two forms of an allele, there are more than two for one gene.
i. The best example for humans is blood. There 3 alleles for blood types in humans: A, B and O. A and B are co dominant while O is recessive.

2. Multiple Alleles – Blood Type
Type A genotypes could be: IAIA or IAi.
Type B genotypes could be: IBIB or IBi.
Type AB genotype is: IAIB
Type O genotype is: ii

3. Practice
A man who is heterozygous for type A blood marries a woman who is heterozygous for type B blood. Find the possible outcomes

4. e. Sex linked traits
i. Autonomies – there are 44 (22, pairs) of non sex chromosomes.
ii. Sex Chromosomes – the 23rd pair of chromosomes are the sex chromosomes.
The genotype for females is XX; the genotype for males is XY.

5. e. Sex linked traits
iii. Sex linked traits – Are genes located on the X chromosome. There is almost no information located on the Y chromosome.
Since males have only one X chromosome they show whatever allele is on the X chromosome, regardless of whether it is dominant or recessive.

6. e. Sex linked traits
iii. This is the only time that a single recessive allele is expressed.
Two examples of sex-linked traits in humans are red/green colorblindness and hemophillia. (A recessive sex linked trait that keeps your blood from clotting.)

7. Color Test

8. Color Test

9. Color Test

10. Color Test

11. Sex linked traits - Colorblindness
If normal vision (N) is dominant to colorblindness (n) give the genotypes for each of the following:
A female carrier: XNXn
A homozygous dominant female: XNXN
Colorblind male: XnY
Colorblind female: XnXn
A male with normal vision: XNY

12. Sex linked traits Who does the male get the X chromosome from? Mother
Who does a male inherit recessive sex linked traits from? Mother
Who are colorblind more often, men or women? Men; no information on Y to mask the recessive trait on X.

13. Practice
A female carrier has a child with a male with normal vision. What are the chances of colorblindness occuring in: Son? Daughter?

14. Practice
A colorblind male has a child with a normal female. Fill out the cross.