1. Non-Mendelian Genetics
Part 2:
Non-Mendelian Genetics

2. Last week we learned about Mundelein Genetics
This week we will learn about Complex patterns of Inheritance.
Complex inheritance-does not follow the patterns that Mendel described.
Review the Questions on board over what we did week one, explain that that was complete dominance

3. Exceptions to Simple Dominance
1. Incomplete dominance
2. Co dominance
3. Multiple alleles
4. Sex-linked

4. Incomplete dominance- When the heterozygous phenotype is intermediate (mix) between those of the two homozygous parents.
Example
AA=red Aa=pink aa=white

5. Incomplete dominance (one allele for a specific trait is not completely dominant over the other allele. This results in a combined phenotype.)
Genotype
Phenotype
Example
Homozygous dominant
Dominant
Curly hair
Heterozygous
Intermediate
(blend)
Wavy hair
Homozygous recessive
Recessive
Straight hair

6. Practice problem: Incomplete dominance
A wildcat comes in three colors, blue, red, and purple. A homozygous (BB) individual is blue, a homozygous (bb) individual is red, and a heterozygous (Bb) individual is purple. What would be the genotypes and phenotypes of the offspring if a blue wildcat were crossed with a red one?

7. P1 Cross Blue X Red BB X bb F1 Genotype: Phenotype:
Key: BB=blue Bb=purple bb=red
BB X bb F1
Genotype:
Phenotype:

8. Codominance- both alleles are expressed, neither allele is dominate over the other.

9. Sickle Cell

10. Codominance (forms of the gene are equally dominant to each other)
Genotype
Phenotype
Example
Homozygous dominant
Dominant
Red horse hair
Heterozygous
both
Roan hair
(red AND white)
Homozygous recessive
Recessive
White horse hair

11. Practice Problem: Codominance
In cattle, reddish coat color is not completely dominant to white coat color. Heterozygous individuals have coats that are roan colored (ie. reddish, but with spots of white hairs).
Show a cross of a homozygous dominate red bull to a roan cow.
(hint roan is heterozygous)

12. P1 Cross Red X Roan BB X Bb F1 Genotype: Phenotype:
Key: BB= Red Bb= Roan (both of red and white) bb= White
BB X Bb F1
Genotype:
Phenotype:

13. Co-Dominance Vs. Incomplete Dominance
Make a poster with a fictitious Animal or plant illustrating Co-Dominance and Incomplete Dominance.
Give your new organism a name and title your poster “ Complex Inheritance pattern of ___________”
Make a “key” with the genotypes and phenotypes listed.
List the parents genotype as homozygous and draw a small image of each then draw one heterozygous offspring larger, list the genotype. (see example)
List and Define the Vocab word at the bottom of poster
Must be COLORED and NEAT!!
You may NOT copy my example think of something on your OWN!!
End Day whats not done is HW.

14. Review What is Complete/Simple dominance What is Incomplete Dominance?
What's Co dominance?
How are they different from each other?
How are the different from Complete Dominance?

15. Can anyone remind me how the law of segregation helps us in making our punnet square?
Remember the law of segregation is what tells us we get one allele from each of our parents.
Law of Segregation –during meiosis the alleles separate from one another so that each gamete receives one allele

16. All along we have been talking about traits that have been determined by only two different alleles. Its true each of us have two alleles for each gene, but that there are more than two options for each allele.

17. Multiple alleles- having more than 2 alleles for a specific trait
Remember a gene is a inherited trait (hair color) an allele is a form of that gene that codes for the phenotype (brown, blond, red, etc)

18. Multiple allele (Multiple alleles can demonstrate a hierarchy of dominance) in this example, there a 4 possible alleles: M, mb , mc , m
Genotype
Phenotype
Example
MM, Mmb, Mmc, Mm
Dominant to all others
Ace beats the King, Queen, Jack
mbmb, mbmc, mbm
Version b (dominant to mc & m)
King beats the Queen & Jack
mcmc, mcm
Version c (dom. to rec.)
Queen beats the Jack mm
Recessive to all others
Jack
there are often hundreds of alleles for any particular gene.

19. Blood cells are an example of multiple alleles and Co-Dominance
As you can count, there are 6 different genotypes & 4 different phenotypes for blood type.

20. Bottom line for Multiple alleles
The presence of multiple alleles allows for an increased number of genotypes and phenotypes, thus creating more variation.
Why might variation be a good thing????

21. Practice Problem: Multiple alleles
A woman with Type O blood and a man who is Type AB have are expecting a child.  What are the possible blood types of the kid?

22. Type O X Type AB
This Chart will Always be provided for you

23. Worksheet Multiple Alleles what’s not done is HW

24. Sex linked Traits

25. Male Genotype: XY Female Genotype: XX
Sex linked
Sex linked traits- characteristic controlled by genes that are on the X chromosome.
*Remember*
Male Genotype: XY Female Genotype: XX

26. Sex-linked (traits carried on sex chromosome, usually X-linked)
Genotype
Phenotype
Example
XHXH
XHY
Non-afflicted, not a carrier
Normal female
Normal male
XHXh
Carrier but not afflicted
Carrier female
*males cannot be carriers!
XhXh
XhY
Both are afflicted
Colorblind female & male

27. Why are more males affected by X-linked traits than females?

28. Why are more males affected by X-linked traits than females?
Males have an XY genotype, since males have only one X chromosome, they are affected by recessive X linked traits more often than females.
Females have an XX genotype and the other X chromosome would likely mask the recessive trait.

29. Sex-Linked Traits Can you see a number inside this circle?
About 8% of males a color blind and only .5% of females

30. Punnett Square XB Y XBXB XB Y Xb XBXb Xb Y XB = Normal
Xb = affected trait
Y= Normal Y chromosome XB Y
XBXB
XB Y Xb
XBXb
Xb Y

31. Practice problem: Sex-linked
Hemophilia is due to a sex-linked recessive gene (Xh) and the normal condition to the gene (XH). Show a cross between a hemophiliac man and a woman does not carry the trait.

32. hemophiliac man X normal woman
Key
XH = Normal
Xh = Hemophiliac
*Remember*
Male Genotype: XY Female Genotype: XX

33. Sex linked traits WS what’s not done is HW

34. Lets review our new terms!!
Sex linked traits- characteristic controlled by genes that are on the X chromosome.
Incomplete dominance- When the heterozygous phenotype is intermediate between those of the two homozygous parents.
Codominance- both alleles are expressed, neither allele is dominate over the other
Multiple alleles- having more than 2 alleles for a specific trait