1. Complex Genetics
Sex-linked
Co-Dominance
Incomplete Dominance

2. What is Complex Genetics?
So far, we’ve been learning about Mendalian Genetics
the study of simple recessive and dominant traits
Complex Genetics is the study of traits that are not simply 1 dominant or 1 recessive characteristic

3. The Four Types of Complex Genetics
Sex-linked Genetics
Co-Dominance
Incomplete Dominance

4. What is Complex Genetics?
So far, we’ve been learning about Mendalian Genetics
the study of simple recessive and dominant traits
Complex Genetics is the study of traits that are not simply 1 dominant or 1 recessive characteristic

5. The Four Types of Complex Genetics
Dihibrid Crosses
Sex-linked Genetics
Co-Dominance
Incomplete Dominance

6. DiHybrid Crosses A Dihybrid cross looks at TWO traits at once
It works JUST like a monohybrid cross but it has more letters :)

7. How to Do a Dihybrid Cross
There are 5 steps to figure out the probability of two traits
1. Look at each individual trait on its own and write out its genotype and phenotype
2. Write out the possible combinations
Each combination should have have one letter from each of the traits
3. Put the parents’ genotype combinations on the outside of the square
4. Fill in the Punnett Square
Determine the outcomes of the possible offspring

8. Now, Let’s Do One!
Step One: Determine the phenotype and genotypes of each of the parents
When Will Smith clasps his hands together, his left thumb is on top, which is a dominant trait (L). He also has a bent pinky finger (B), which is a dominant to a straight pinky finger. Will is heterozygous for his left thumb on top and heterozygous for a bent pinky. Jada Pinkett Smith is heterozygous for her left thumb on top, and is heterozygous for bent pinky fingers.
Will’s Genotype__________ Phenotype________
Jada’s Genotype_________ Phenotype_________

9. Step Two Step Two: Write out all of the possible Combinations!
Use the FOIL technique (first, outside, inside, last)
Will’s Genotype_______________
Foil for the possible Combinations:
Jada’s Genotype______________

10. Step Three
Place the parent genotypes on the outside of the punnett square.

11. Step Four
Fill out the Punnett Square!

12. Step Five: Determine the Possible Outcomes
How do we figure out possibilities?
Possibilities:
BBLL
BBLl
BbLL
BbLl
Bbll
bbLL
bbLl
bbll BL Bl bL bl
BBLL
BBLl
BbLL
BbLl
Bbll
bbLL
bbLl
bbll

13. Step Five Continued Phenotypes Possibilities Dominant Dominant
Dominant Recessive
Recessive Dominant
Recessive Recessive BL Bl bL bl
BBLL
BBLl
BbLL
BbLl
Bbll
bbLL
bbLl
bbll

14. Sex-Linked Traits
Some traits are only on your last two chromosomes, which are known as the Sex Chromosomes
This means that gender affects the traits
X-Linked traits: The trait is found only on an X chromosome.
A girl will have 2 copies of the trait (one on each X chromosomes)
A boy will have only ONE copy of the trait (they only have one X chromosome)

15. Sex Linked Carriers

16. Sex Linked Example
Colorblindness is a X chromosome sex-linked disorder. Color-blindness is recessive. A Heterozygous female and a Colorblind male are worried about their future children... fill out a punnett square to figure out their possibilities:
Mother: Genotype______ Phenotype______
Father: Genotype______ Phenotype______

17. Co-Dominance
Codominance occurs when the trait of each allele shows up.
Both alleles are equally dominant!!
The common example of Codomiance:
Blood Types!

18. Blood Types
What are the different types of blood types? A B AB O

19. The Genotypes of the Four Blood Types?

20. Let’s Try Blood Typing!
Beyonce and Jay Z have recently been blood typed. Beyonce has an AB blood type and JayZ is Heterozygous A. Complete the punnett Square:
Beyonce: Genotype____
Jay Z: Genotype _____
Possible child Genotype _______
________
Possible child Phenotypes ________

21. Incomplete Dominance
Formal Definition: Incomplete dominance is a form of intermediate inheritance in which one allele for a specific trait is not completely dominant over the other allele. This results in a combined phenotype
In Otherwords:
How is this different from Co-Dominance?

22. Snap Dragon Flowers

23. Let’s Try Incomplete Dominance
Tulips are beautiful flowers. Tall tulips have a genotype of TT and short tulips have a genotype of tt. Yet, some tulips are of medium length. Medium height tulips occur when a tulip is heterozygous for height. A homozygous tall tulip and a short tulip mate. What are their possible offspring?
Tulip One: Genotype______ Phenotype:_______
Tulip Two: Genotype______ Phenotype:_______