1. Dihybrid Crosses and Different Patterns of Inheritance

2. Dominant/Recessive Pattern when two different alleles are present, one is expressed (dominant) while the other is hidden (recessive)

3. Dihybrid Cross Two Trait Punnett Squares

4. breeding that involves two unique traits –Seed Shape: R = round, r = wrinkled –Seed Color: Y = yellow, y = green

5. Dihybrid Cross Two Trait Punnett Squares

8. Dihybrid Example A plant that is heterozygous for seed shape (Rr) and heterozygous for seed color (Yy) is self-pollinated. What will the genotypic and phenotypic ratios be of the offspring?

9. Dihybrid Example

10. RYRyrYry RY Ry rY ry

11. Dihybrid Example RYRyrYry RYRRYYRRYyRrYYRrYy RyRRYyRRyyRrYyRryy rYRrYYRrYyrrYYrrYy ryRrYyRryyrrYyrryy

12. Dihybrid Example Genotypic Ratio: –1 RRYY : 2 RRYy : 1 RRyy : 2 RrYY : 4 RrYy : 2 Rryy : 1 rrYY : 2 rrYy : 1 rryy Phenotypic Ratio: –9 Round & Yellow : 3 Round & Green : 3 Wrinkled & Yellow : 1 Wrinkled & Green

13. Incomplete dominance a condition in which a heterozygous individual appears in-between two different phenotypes –neither allele is completely dominant two alleles resulting in three phenotypes

14. Incomplete dominance heterozygous individuals have a phenotype somewhere in the middle of the two alleles Example in humans –a straight-haired parent and a curly-haired parent will produce a wavy-haired child use an apostrophe (’) or superscript letters to indicate different alleles –S = straight, S’ = curly SS = straight, SS’ = wavy, S’S’ = curly

15. Incomplete dominance

16. Codominance two alleles are expressed at the same time Example in humans –ABO blood type in humans

17. Codominance in Shorthorn Cattle CWCWCWCW CWCRCWCR CRCRCRCR

18. Codominance in Camellia Flowers CWCWCWCW CWCPCWCP CPCPCPCP

19. Codominance use superscript letters to show different alleles –C W = white, C R = red C W C W = white, C R C R = red, C W C R = roan

20. Multiple alleles genes with 3 or more alleles possible for the same character Example in humans –ABO blood type in humans

21. Multiple Alleles & Codominance

22. Multiple alleles use capital and lowercase letters and/or superscript letters to show different alleles –T A = __________, T B = __________, t = __________ T A T A = __________, T A t = __________, T B T B = __________, T B t = __________, T A T B = __________, tt = __________

23. Multiple alleles use capital and lowercase letters and/or superscript letters to show different alleles –T A = type A blood, T B = __________, t = __________ T A T A = __________, T A t = __________, T B T B = __________, T B t = __________, T A T B = __________, tt = __________

24. Multiple alleles use capital and lowercase letters and/or superscript letters to show different alleles –T A = type A blood, T B = type B blood, t = __________ T A T A = __________, T A t = __________, T B T B = __________, T B t = __________, T A T B = __________, tt = __________

25. Multiple alleles use capital and lowercase letters and/or superscript letters to show different alleles –T A = type A blood, T B = type B blood, t = type O blood T A T A = __________, T A t = __________, T B T B = __________, T B t = __________, T A T B = __________, tt = __________

26. Multiple alleles use capital and lowercase letters and/or superscript letters to show different alleles –T A = type A blood, T B = type B blood, t = type O blood T A T A = type A blood, T A t = __________, T B T B = __________, T B t = __________, T A T B = __________, tt = __________

27. Multiple alleles use capital and lowercase letters and/or superscript letters to show different alleles –T A = type A blood, T B = type B blood, t = type O blood T A T A = type A blood, T A t = type A blood, T B T B = __________, T B t = __________, T A T B = __________, tt = __________

28. Multiple alleles use capital and lowercase letters and/or superscript letters to show different alleles –T A = type A blood, T B = type B blood, t = type O blood T A T A = type A blood, T A t = type A blood, T B T B = type B blood, T B t = __________, T A T B = __________, tt = __________

29. Multiple alleles use capital and lowercase letters and/or superscript letters to show different alleles –T A = type A blood, T B = type B blood, t = type O blood T A T A = type A blood, T A t = type A blood, T B T B = type B blood, T B t = type B blood, T A T B = __________, tt = __________

30. Multiple alleles use capital and lowercase letters and/or superscript letters to show different alleles –T A = type A blood, T B = type B blood, t = type O blood T A T A = type A blood, T A t = type A blood, T B T B = type B blood, T B t = type B blood, T A T B = type AB blood, tt = __________

31. Multiple alleles use capital and lowercase letters and/or superscript letters to show different alleles –T A = type A blood, T B = type B blood, t = type O blood T A T A = type A blood, T A t = type A blood, T B T B = type B blood, T B t = type B blood, T A T B = type AB blood, tt = type O blood

32. Sex-linked a trait that is determined by a gene found on one of the sex chromosomes –many traits are located only on the X chromosome

33. Sex-linked leads to many recessive characteristics being common in males –males only have one copy of the X chromosome Examples in humans –colorblindness, hemophilia (bleeder’s disease)

34. Sex-linked must use sex chromosomes as part of Punnett Square allele identification –Ex: X N = X chromosome with a normal gene, X n = X chromosome with a colorblind gene, Y = no gene

35. Polygenic Inheritance several genes influencing one character Example in humans: –height, weight, hair color, and skin color won’t use a Punnett Square with this type of inheritance

36. Environmental influences conditions around organisms also influence their phenotype

37. Environmental influences

39. Examples in humans: –height and weight are influenced by nutrition