1. Agenda Lab Quiz #9 Turn in Microworlds
DO NOT TURN IN PRE-LAB YET!! We’ll go over it.

2. Punnett Square p P P p PP Pp Pp pp
Shows possible combinations of alleles
Demonstrates Mendel’s Laws
Purple flower allele: P
White flower allele: p p P P p PP Pp Pp pp

3. Punnett Square Problems
Heterozygous x white
Homozygous yellow (Y) x homozygous green (y)

4. When it’s not so simple
INCOMPLETE DOMINANCE: heterozygotes have a unique or intermediate phenotype

5. When it’s not so simple
INCOMPLETE DOMINANCE: heterozygotes have a unique or intermediate phenotype HH
Homozygous
for ability to make
LDL receptors
Genotypes: Hh
Heterozygous
Phenotypes:
LDL
receptor
Cell
Normal
Mild disease
Severe disease hh
for inability to make

6. When it’s not so simple RR = red hair rr = white hair
CODOMINANCE: both alleles are expressed equally in the phenotype of a heterozygote
RR = red hair
rr = white hair
Rr = red hairs and white hairs

7. Codominant Alleles - Bloodtype
Three alleles for blood type A B O
This allele is for a protein (blood antigen) on the outer surface of red blood cells

8. Codominant Alleles - Bloodtype
ANTIGENS
ANTIBODIES
A gene  A protein
B gene  B protein
O gene  no protein
Your body produces antibodies to any protein that you don’t have the gene for

9. Codominant Alleles - Bloodtype

10. Blood Type & Multiple Alleles

11. Sex Linkage Sex Chromosomes = X and Y
What do you notice about the X and the Y chromosomes?
X chromosome has many genes
Y chromosome has few

12. Sex Linkage
Female = ?
Male = ? X X X Y

13. Riddle me this… Xh XH Y XHXH XHY XhY XHXh
Hemophilia is a recessive sex-linked disease. Are boys or girls more likely to suffer from hemophilia? WHY? XH Xh Y
XHXH
XHY
XhY
XHXh