The document discusses different patterns of inheritance beyond simple dominance: 1) Incomplete dominance, where the heterozygous phenotype is intermediate between the homozygous phenotypes. Examples include snapdragons and carnations. 2) Codominance, where both alleles are expressed in the heterozygote rather than blending. Examples include checkered chickens, roan horses, and variegated clover. 3) Multiple alleles, where more than two alleles control a trait. Examples include human blood types and coat colors in rabbits.

1. Incomplete Dominance, Codominance and Multiple Alleles

2. INCOMPLETE DOMINANCE Incomplete Dominance- Pattern of gene expression in which the phenotype of a heterozygous individual is intermediate between those of the parents. Cases in which one allele is not completely dominant over another. Example: Snapdragons and Carnations

3. Incomplete Dominance- F 1 generation

4. Incomplete Dominance- F 2 generation

6. CODOMINANCE Codominance - The condition in which both alleles in a heterozygous organism are expressed. BOTH alleles contribute to the phenotype. The two alleles don’t blend , but are rather both present in the offspring. Examples- Checkered Chickens, Roan Horses, Roan Cows, Variegated Clover.

7. B B W W BW BW BW BW Codominance White chicken Black chicken Checkered Checkered Checkered Checkered Checkered Black White

8. http://search.vadlo.com/b/q?rel=2&keys=Dominance+Incomplete+Dominance+Codominance+PPT Roan Horse

9. Roan Cattle Variegated Clover http://3.bp.blogspot.com/_zUPrgMM5tUg/SSVdrs59_uI/AAAAAAAAAA8/qJGjG2nZPhk/s200/codominance.GIF http://www.ccs.k12.in.us/chsteachers/BYost/Biology%20Notes/CH11notescoincompletedom_files/image004.jpg

10. Multiple Alleles Multiple Alleles- Genes which have more than two alleles. It is common for more than 2 alleles to control a trait in a population Multiple alleles can only be studied in populations since each individual only has 2 alleles for a trait. Examples: human blood types, fruit fly eye color, c oat color in rabbits: C , cch , ch , and c .

11. Complex Inheritance and Human Heredity Coat Color of Rabbits Light gray Dark gray Himalayan Albino Chinchilla 11.2 Complex Patterns of Inheritance Chapter 11

12. ABO Blood Type ABO blood type in humans is determined by three alleles: I A I B i I A and I B are codominant alleles. Both I A and I B are dominant to the allele i. Genotype Blood Type I A I A A I A i A I B I B B I B i B I A I B AB ii O

13. Complex Inheritance and Human Heredity Multiple Alleles Blood groups in humans ABO blood groups have three forms of alleles. 11.2 Complex Patterns of Inheritance Chapter 11

14. Donor-recipient compatibility Note: Type O blood may be transfused into all the other types = the universal donor . Type AB blood can receive blood from all the other blood types = the universal recipient . © 2007 Paul Billiet ODWS O AB B Donor A O AB B A Type Recipient = Safe transfusion = Unsafe transfusion