1. Non-Mendelian Genetics

5. Blood types There are three alleles that code for blood type A (IA)
B (IB)
O (i)
A and B are codominant
O is recessive to both A and B
Results in 4 possible phenotypes for blood type:
Blood type
Possible Genotypes A
IAIA or Iai B
IBIB or IBi AB
IAIB O ii

6. Sample problem #1 Both the father and mother have type AB blood
Genotype of mother and father ______

7. Sample problem #2
A father is type A heterozygous and the mother is type B heterozygous
Genotype of mother and father ______

8. Sex Chromosomes X Y

9. some genes are unique only to the Y chromosome
X chromosome
has over 1,000 genes
most genes on the X chromosome do not have corresponding alleles on the Y chromosome
Y chromosome
has only a few dozen genes
some genes are unique only to the Y chromosome

10. Sex-Linked Traits
Those traits whose genes are found on the X chromosome but NOT on the Y chromosome
Red-green colorblindness
Male pattern baldness
Hemophilia
Muscular dystropy

12. Color Blindness “tests”

13. Females = XX –carry 2 alleles for a sex-linked trait
Males = XY – only carry 1 allele for a sex-linked trait, so it is easier for them to get sex-linked diseases

14. Sex-Linked Traits, cont.
Males receive sex-linked traits from their mother because their mother gives them the X chromosome and their father gives them the Y chromosome

15. Example of Sex-Linked Trait
H = Normal blood clotting
h = Hemophilia
These will be written as a superscript next to the X and Y that represent the sex chromosomes

16. Example of Sex-Linked Trait
Normal male:
Male with Hemophilia:
Normal female (not a carrier for hemophilia – homozygous):
Normal female (carrier for hemophilia – heterozygous):
Female with Hemophilia:
XHY
XhY
XHXH
XHXh
XhXh

17. Sample problem #1. XHXh x XHY
Chances of:
a. hemophiliac child?
b. hemophiliac son?
c. hemophiliac daughter?
d. daughter who is carrier?
¼ or 25%
XH Xh XH Y
XHXh
XHXH
½ or 50%
XHY
XhY 0%
½ or 50%

18. 2. A woman who is a carrier for hemophilia marries a hemophiliac man.
XHXh x XhY
Chances of:
a. hemophiliac child?
b. hemophiliac son?
c. hemophiliac daughter?
XH Xh
2/4 or 50% Xh Y
XhXh
XHXh
½ or 50%
XHY
XhY
½ or 50%