1. Mendel Law Exceptions
Biology Standard 3a

4. Punnett Square

5. Some alleles are neither dominant nor recessive, and many traits are controlled by multiple alleles and genes.

6. # 1:Codominance
Codominance

7. Codominance
A condition in which both alleles show up in the phenotype.
Neither allele is recessive.

8. Codominance: Piebald Black-Pastel Ball Python

9. 2) Incomplete Dominance

10. 2) Incomplete Dominance
Cross white roses (WW) with red roses (RR) Pink roses (RW)!
Heterozygous offspring are in b/t the 2 homozygous phenotypes. Blending!

11. 3) Polygenic Traits

12. 3) Polygenic Traits Traits that are controlled by 2 or more genes.
Ex: skin/eye color in humans controlled by > 4 genes.
Creates wide range of trait

13. 4) Crossing Over

14. Creates new combos of alleles (differing mom/dad)
4) Crossing Over
Pieces of gene on homologous chromosomes can get swapped during meiosis.
Creates new combos of alleles (differing mom/dad)

15. Multiple Alleles Some genes have more than 2 alleles.
Ex: Blood type: A, B, AB, O
But, you still will only get 2 copies of the allele, from mom and dad!

16. Tie into Protein Synthesis
Traits that show up in phenotype came from DNA exon originally.
DNA  mRNA  protein (trait)

17. Gene Linkage Genes for traits can be inherited together  linked.
Each chromosome is actually a group of linked genes.
Ex: red eyes and mini wings on the fruit fly….found on same chromosome.