1. BIO: Agenda Today: Alternate patterns of inheritance
Notes/4 examples. These are slightly different than the ones we’ve done so far!
Practice WS
Unit 5 Test Wed 1/31, Thurs 2/1

2. Incomplete Dominance Red Snapdragon R r White Snapdragon
One allele is not completely dominant over the other, resulting in a mix of traits in the heterozygous offspring. r R
Red Snapdragon
White
Snapdragon

3. Incomplete Dominance Pink Snapdragon r R Pink Snapdragon
Incomplete dominance is not support for the blending theory of inheritance; the white gene doesn’t blend with the red gene because the red and white traits can come back in the 2nd generation (as long as the individual is homozygous) R r
Pink Snapdragon
Pink
Snapdragon

4. Incomplete Dominance
With incomplete dominance, since one trait is not dominant over the other the use of capital and lowercase letters could be confusing. So, capital letters are used with superscripts to distinguish between the two alleles.

5. FW FW FB FW FB
FBFW FB
FBFB FW FW

6. Codominance
AB Blood type shows another pattern of inheritance called CODOMINANCE because the A and B alleles are dominant together and are expressed EQUALLY
TYPE A
TYPE B
TYPE AB
TYPE O

7. O O G GO G

8. Multiple Alleles
A gene can have more than two alleles that code for the trait associated with it.
This results in the possibility of more than 3 phenotypes
Ex: human blood type

9. IB i
IAIB IA i

10. Sex-linked Alleles
The gene of interest is located on the X- chromosome. This means that regardless of whether the allele is dominant or recessive, males will always express the trait for whatever allele they have because they only have one X chromosome.
Examples: Hemophilia, red-green color-blindness.

12. XN Y XN
XNXN Xn

13. Polygenic Inheritance
Multiple pairs of genes affect a single characteristic/trait
Ex: Eye Color
Brown B_ _ _
Green bbG_
Blue bbgg

14. Alternate Patterns of Inheritance
Get this stamped!