7-2 Different Dominances

1. 7-2 Different Dominances

2. Co-Dominance • Some alleles are neither dominant nor recessive, and many traits are controlled by multiple alleles or multiple genes.

3. Co-Dominance • Some alleles are neither dominant nor recessive, and many traits are controlled by multiple alleles or multiple genes. • Some genes have more than two alleles and none of them are dominant

4. Co-Dominance • Some alleles are neither dominant nor recessive, and many traits are controlled by multiple alleles or multiple genes. • Some genes have more than two alleles and none of them are dominant • In rabbits four color patterns are visible, on the same gene. Therefore it has four different alleles, with varying dominance

5. Co-Dominance • Human blood typing is dependent upon a multiple allele gene. Type A, Type B, Type AB, Type O

6. Co-Dominance • Human blood typing is dependent upon a multiple allele gene. Type A, Type B, Type AB, Type O • The gene is expressed in a protein on the outside of the red blood cells called an Antigen

7. Co-Dominance • Human blood typing is dependent upon a multiple allele gene. Type A, Type B, Type AB, Type O • The gene is expressed in a protein on the outside of the red blood cells called an Antigen • Two of them are co-dominant when paired A and B gives type AB

8. Co-Dominance • One antigen is recessive expressed as i

9. Co-Dominance • One antigen is recessive expressed as i • When A or B is present the type follows the dominant Ai or Bi expressed as A or B

10. Co-Dominance • One antigen is recessive expressed as i • When A or B is present the type follows the dominant Ai or Bi expressed as A or B • When the recessive combination ii exists the type is O

11. Range of genotypes: IAIA IBIB or or IAi IAIB IBi ii Blood Types: A AB B O Fig. 8-9, p.118

12. Co-Dominance • Blood transfusions are dependant upon this gene

13. Co-Dominance • Blood transfusions are dependant upon this gene • Since they are antigens, they fight disease including other antigens

14. Co-Dominance • Blood transfusions are dependant upon this gene • Since they are antigens, they fight disease including other antigens • A will reject B, B will reject A so one cannot donate blood to the other

15. Co-Dominance • Blood transfusions are dependant upon this gene • Since they are antigens, they fight disease including other antigens • A will reject B, B will reject A so one cannot donate blood to the other • Antigen i will not be rejected so it is the universal donor

16. Co-Dominance • Blood cells with both antigens AB will recognize all antigens or none so it is the universal acceptor

17. Incomplete Dominance • A cross between two alleles which results in a hybrid with characteristics of both alleles

18. Incomplete Dominance • A cross between two alleles which results in a hybrid with characteristics of both alleles • Red flowered and white flowered alleles of the same gene will produced a pink-flowered plant in the hybrid.

19. homozygous parent homozygous parent X All F1 offspring heterozygous for flower color: Cross two of the F1 plants and the F2 offspring will show three phenotypes in a 1:2:1 ratio: Fig. 8-10, p.118

20. Incomplete Dominance • A cross between two alleles which results in a hybrid with characteristics of both alleles • Red flowered and white flowered alleles of the same gene will produced a pink-flowered plant in the hybrid. • Snapdragons - text

21. Incomplete Dominance • A cross between two alleles which results in a hybrid with characteristics of both alleles • Red flowered and white flowered alleles of the same gene will produced a pink-flowered plant in the hybrid. • Snapdragons - text • Poinsettias

22. Multiple Genes • Some traits have more than one gene controlling the characteristic

23. Multiple Genes • Some traits have more than one gene controlling the characteristic • In Labrador retrievers three color patterns are visible, on two different genes.

24. BLACK LABRADOR YELLOW LABRADOR CHOCOLATE LABRADOR Fig. 8-11, p.119

25. Multiple Genes • Some traits have more than one gene controlling the characteristic • In Labrador retrievers three color patterns are visible, on two different genes. • Therefore it has four different alleles, with varying dominance

26. Fig. 8-11, p.119

27. Multiple Genes • Skin color in humans is dependant upon the interaction of four different genes.

28. Multiple Genes • Skin color in humans is dependant upon the interaction of four different genes. • Varying degrees of color in skin is seen as well as features associated with colored skin – thick lips, kinked hair

29. 8-3 Environmental Factors • Different traits change due to environment

30. Environmental Factors • Different traits change due to environment • Rabbits change coat every winter – temperature effects the gene for melanin (color) deposit in hair causing white hair

31. Stepped Art Fig. 8-16, p.122

32. Environmental Factors • Different traits change due to environment • Rabbits change coat every winter – temperature effects the gene for melanin (color) deposit in hair causing white hair • Plants are sensitive to elevation

33. Environmental Factors • Different traits change due to environment • Rabbits change coat every winter – temperature effects the gene for melanin (color) deposit in hair causing white hair • Plants are sensitive to elevation • People grow taller, bigger when allowed a richer diet – you are bigger than your ancestors