1. Non-Mendelian Genetics

2. Mendelian Genetics: Dominant & Recessive Review  One allele is DOMINANT over the other (because the dominant allele can “mask” the recessive allele) genotype: PP phenotype: purple genotype: pp phenotype: white genotype: Pp phenotype: purple

3. Review Problem: Dominant & Recessive  In pea plants, purple flowers (P) are dominant over white flowers (p). Show the cross between two heterozygous plants. PpPp P p pp Pp PP - PP (25%) Pp (50%) pp (25%) - ratio 1:2:1 - purple (75%) white (25%) - ratio 3:1 GENOTYPES: PHENOTYPES:

4. Non-Mendelian Genetics  Incomplete Dominance  Codominance  Multiple Alleles  Polygenic Traits  Sex-Linked Traits

5. Incomplete Dominance  a third (new) phenotype appears in the heterozygous condition as a BLEND of the dominant and recessive phenotypes. Ex - Dominant Red (R) + Recessive White (r) = Hybrid Pink (Rr) RR = redrr = whiteRr = pink

6. Problem: Incomplete Dominance  Show the cross between a pink and a white flower. - RR (0%) Rr (50%) rr (50%) - ratio 1:1 - pink (50%); white (50%) - ratio 1:1 R r rrrr rr Rr rr Rr GENOTYPES: PHENOTYPES:

7. Codominance  in the heterozygous condition, both alleles are expressed equally with NO blending! Represented by using two DIFFERENT capital letters.  Example: Dominant Black (B) + Dominant White (W) = Speckled Black and White Phenotype (BW)  Sickle Cell Anemia - NN = normal cells SS = sickle cells NS = some of each

8. Codominance Example: Speckled Chickens  BB = black feathers  WW = white feathers  BW = black & white speckled feathers  Notice – NO GRAY! NO BLEND! Each feather is either black or white

9. Codominance Example: Rhodedendron  R = allele for red flowers  W = allele for white flowers  Cross a homozygous red flower with a homozygous white flower.

10. Codominance Example: Roan cattle  cattle can be red (RR – all red hairs) white (WW – all white hairs) roan (RW – red and white hairs together)

11. Codominance Example: Appaloosa horses  Gray horses (GG) are codominant to white horses (WW). The heterozygous horse (GW) is an Appaloosa (a white horse with gray spots).  Cross a white horse with an appaloosa horse. W W GWGW GW WW

12. Problem: Codominance  Show the cross between an individual with sickle-cell anemia and another who is a carrier but not sick. N S SSSS SS - NS (50%) SS (50%) - ratio 1:1 - carrier (50%) sick (50%) - ratio 1:1 GENOTYPES: PHENOTYPES:

13. Multiple Alleles  there are more than two alleles for a gene. Ex – blood type consists of two dominant and one recessive allele options. Allele A and B are dominant over Allele O (i)

14. Multiple Alleles: Lab Mouse Fur Colors  Fur colors (determined by 4 alleles): black agouti yellow

15. Multiple Alleles: Rabbit Fur Colors  Fur colors (determined by 4 alleles): full, chinchilla, himalayan, albino

16. Multiple Alleles: Blood Types (A, B, AB, O)  Rules for Blood Types: A and B are co-dominant (Both show) AA or I A I A = type A BB or I B I B = type B AB or I A I B = type AB A and B are dominant over O (Regular dom/rec) AO or I A i = type A BO or I B i = type B OO or ii = type O

17. Multiple Alleles: Blood Types (A, B, AB, O)

18. Phenotype Possible Genotype(s) Allele (antigen) on RBC surface Can Donate Blood To Can Receive Blood From A IAiIAIAIAiIAIA AA, ABA, O B IBiIBIBIBiIBIB BB, ABB, O ABIAIBIAIB A, B, AB, O OiiO A, B, AB, OO

19. Problem: Multiple Alleles  Show the cross between a mother who has type O blood and a father who has type AB blood. - Ai (50%) Bi (50%) - ratio 1:1 - type A (50%) type B (50%) - ratio 1:1 GENOTYPES: PHENOTYPES: i i ABAB Ai Bi Ai Bi

20. Problem: Multiple Alleles  Show the cross between a mother who is heterozygous for type B blood and a father who is heterozygous for type A blood. -AB (25%); Bi (25%); Ai (25%); ii (25%) - ratio 1:1:1:1 -type AB (25%); type B (25%) type A (25%); type O (25%) - ratio 1:1:1:1 GENOTYPES: PHENOTYPES: A i BiBi AB ii Bi Ai

21. Polygenic Traits  traits produced by multiple genes  example: skin color

22. Sex-Linked Traits  Gene is attached to the X chromosome only, not found on the Y chromosome at all. (women have XX, men have XY chromosomes). These disorders are more common in boys.  examples: red-green colorblindness

23. Sex-Linked Traits  in males, there is no second X chromosome to “mask” a recessive gene. If they get an X with the disorder, they have it. Girls must inherit defective X’s from both parents.

25. Sex-Linked Traits A: 29, B: 45, C: --, D: 26  Normal vision A: 70, B: --, C: 5, D: --  Red-green color blind A: 70, B: --, C: 5, D: 6  Red color blind A: 70, B: --, C: 5, D: 2  Green color blind