1. Part 2: Non-Mendelian Genetics

2. We’ve learned about Mendelian Genetics. Now week we will learn about Complex Patterns of Inheritance. Complex inheritance does not follow the patterns that Mendel described.

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

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

5. Incomplete Dominance ( One allele for a specific trait is not completely dominant over the other allele. This results in a combined (blended) phenotype. ) GenotypePhenotypeExample Homozygous dominant DominantCurly hair Heterozygous dominant Intermediate (blend) Wavy hair Homozygous recessive RecessiveStraight 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. Key: BB=blue Bb=purple bb=red P1 Cross Blue X Red BB X bb F1 Genotype : Phenotyp e:

8. Codominance - both alleles are expressed. Neither allele is dominate over the other. PP = Pink ww = white Pw = Pink and white

9. A Case of Codominance: Sickle Cell Anemia

10. Codominance (Forms of the gene are equally dominant to each other.) GenotypePhenotypeExample Homozygous dominant DominantRed horse hair Heterozygous dominant Intermediate (mixed) Roan hair (red AND white) Homozygous recessive RecessiveWhite 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. Key: BB= Red Bb= Roan (both of red and white) bb= White P1 Cross Red X Roan BB X Bb F1 Genotype : Phenotyp e:

13. Co-Dominance Vs. Incomplete Dominance Make a poster with a fictitious animal or plant illustrating Co-Dominance and Incomplete Dominance. 1.Give your new organism a name and title your poster “ Complex Inheritance pattern of ___________” 2.Make a “key” with the genotypes and phenotypes listed. 3.List the parents genotype and draw a small image of each then draw one offspring larger, list the genotype. (see example) 4.List and Define the Vocab word at the bottom of poster 5.Must be COLORED and NEAT!! You may NOT copy my example think of something on your OWN!!

14. What is Incomplete Dominance? What is Codominance? How are they different from each other? How are they different from Complete Dominance?

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

16. Multiple allele (Multiple alleles can demonstrate a hierarchy of dominance) in this example, there a 4 possible alleles: M, m b, m c, m GenotypePhenotypeExample MM, Mm b, Mm c, MmDominant to all others Ace beats the King, Queen, Jack m b m b, m b m c, m b mVersion b (dominant to m c & m) King beats the Queen & Jack m c m c, m c mVersion c (dom. to rec.) Queen beats the Jack mmRecessive to all others Jack The hair color of chinchillas would be an example of a multiple allelic trait.

17. Chinchilla Genetics http://www.chinchillachronicles.com/chinchilla_geneti cs.html

18. 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.

19. 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????

20. 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?

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

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

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

24. Sex-linked (traits carried on sex chromosome, usually X-linked) GenotypePhenotypeExample XX XY Non-afflicted, not a carrier Normal female Normal male XcXXcX Carrier but not afflicted Carrier female *males cannot be carriers! XcXcXcYXcXcXcY Both are afflicted Colorblind female & male

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

26. 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.

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

28. Punnett Square X B = Normal X b = affected trait Y= Normal Y chromosome XBXB Y XBXB XBXBXBXB X B Y XbXb XBXbXBXb X b Y

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

30. hemophiliac man X normal woman *Remember* Male Genotype: XYFemale Genotype: XX Key X h = Normal X H = Hemophiliac

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

32. 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