1. Non-Mendelian Genetics
(Odd ball circumstances that Mendel’s work did not account for)

2. Youtube link for Non-Mendelian Genetic Topics
As you are viewing this, reference the slides in this powerpoint to help you break down this information OR you may want to print these slides so you can follow along with the video.

3. Contributions to Non-Menelian Genetics
Thomas Hunt Morgan
Contributions to Non-Menelian Genetics
Included:
Gene Linkage
Sex-linkage

4. Gene Linkage

5. Thomas Hunt Morgan – Fruit flies
Gene linkage – the closer genes are in location to one another on the SAME chromosome, the greater the possibility of recombination of the parent’s PHENOtypes (traits recombining & crossing over) of offspring.
Anytime the outcomes of offspring in a Punnet square probability result are less than 50% = it verifies that those genes that are located on the SAME chromosome!
Vestigial wings - - the term vestigial in this case means = wings that aren't formed enough to allow for true flight (these flies can jump from place to place)

6. Vestigial wings – Drosophila fly
On the left is a picture of a fruit fly with very small wings. This trait arose through a mutation in the vestigial gene, which codes for wing type. The fly on the left carries two copies of the mutant form of this gene. The fly shown on the right is the wild type. It carries two normal (the “wild” types) copies of this gene.

7. Multiple Genes

8. Multiple Genes
Multiple genes = more than 2 genes are responsible for determining traits such as hitchhikers thumb or height.
They become a variation within a range of extreme differences ie: There are probably 6-7 genes that actually determine your height. It is not as cut and dry as saying “tall” or “short.”

9. Multiple Alleles vs Polygenic Traits
The difference between multiple alleles and polygenic traits is …. Multiple alleles (height, blood type) refers to different versions of one gene…. And Polygenic traits refers to a single trait which is controlled by multiple genes (each with multiple alleles) ie: Skin color

10. Sex-linkage

11. Sex Linkage
Sex linkage = some traits on genes that are only found on the sex genes
ie: Hemophilia (Inability for blood to clot), Colorblindness
Trait is carried on the “X” chromosome
Females can be carriers of trait for colorblindness, however, it is very uncommon for females to inherit the trait for colorblindness
Males have a higher propensity to inherit colorblindness because they inherit the X chromosome with the mutation for colorblindness: Xc

12. Punnet Square for Colorblindness
Because the NORMAL X chromosome dominates the trait for vision that detects color, (meaning it does NOT carry the trait for colorblindness) there is only a 25% chance for colorblindness to surface in an individual IF the mother is a carrier for colorblindness.
Xc X X Y
Xc X
X X
Xc Y
X Y