1. Inheritance Patterns

2. Incomplete Dominance
The heterozygous (hybrid) phenotype is somewhere in-between the homozygous phenotypes
If R = red and r = white
Rr = pink

3. We still use capital (dominant) and lowercase (recessive) letters
And the same letter!

4. +

5. Co-Dominance
Both alleles of a gene are expressed – Equal dominance (like co-workers)
We write alleles as 2 different capital letters
BB = Black feathers
WW = White feathers
BW = Speckled black and white feathers

6. Black (BB)
White (WW)
Black & White (BW)

7. White (WW)
Red (RR)
Roan (RW)

8. Multiple Alleles A gene that is controlled by 3 or more alleles
Blood Groups – ABO
IA :has only antigen A
IB : has antigen B
i: has neither antigens = Type O
IAIB : has both A and B antigens

12. Blood Transfusions Recipient – receives blood Donor – donates blood
You can only receive blood that has the same antigens on its cells

13. Rh Antigen Rh antigen is also found on red blood cells
Do not have antigen = Rh negative
Have antigen = Rh positive

14. Sex-Linked Females = XX Males = XY
If a trait is carried on the X chromosome, a male has only 1 copy
It is more likely that a recessive trait will show up on a male than a female. Why?

18. Polygenic Traits
Many genes are involved in controlling the phenotype