1. Non-Mendelian Genetics

2. Incomplete Dominance and Codominance
Mendelian Genetics
4/6/2019
Incomplete Dominance and Codominance
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3. Mendelian Genetics
4/6/2019
Incomplete Dominance
F1 hybrids have an appearance somewhat in between the phenotypes of the two parental varieties.
Example: snapdragons (flower)
red (RR) x white (rr)
RR = red flower
rr = white flower r R
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4. Incomplete Dominance
BLENDING
Red(RR) + White (rr) =Pink (Rr)

5. Incomplete Dominance r R r All Rr = pink (heterozygous pink)
Mendelian Genetics
4/6/2019
Incomplete Dominance r R r
All Rr = pink
(heterozygous pink)
produces the
F1 generation Rr
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6. Mendelian Genetics
4/6/2019
Incomplete Dominance
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7. -Spots, Stripes, Patches
Mendelian Genetics
4/6/2019
Codominance
BOTH SHOW UP
-Spots, Stripes, Patches
Red + White = red and white spots
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8. Codominance Codominance can also happen with colors R- Red r- White
Genotype: Rr Phenotype: Spotted r R Rr

10. Mendelian Genetics
4/6/2019
Codominance
Two alleles are expressed (multiple alleles) in heterozygous individuals.
Example: blood type
1. type A = IAIA or IAi
2. type B = IBIB or IBi
3. type AB = IAIB
4. type O = ii
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11. Question: If a boy has a blood type O and
Question: If a boy has a blood type O and his sister has blood type AB, what are the genotypes and phenotypes of their parents?

12. Codominance Answer: IB IA i IAIB ii Parents: genotypes = IAi and IBi
Mendelian Genetics
4/6/2019
Codominance
boy - type O (ii) X girl - type AB (IAIB)
Answer: IB IA i
IAIB ii
Parents:
genotypes = IAi and IBi
phenotypes = A and B
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13. Codominance Problem Example: homozygous male Type B (IBIB)
Mendelian Genetics
4/6/2019
Codominance Problem
Example: homozygous male Type B (IBIB)
x heterozygous female Type A (IAi) IB IA i
IAIB
IBi
1/2 = IAIB
1/2 = IBi
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14. Another Codominance Problem
Mendelian Genetics
4/6/2019
Another Codominance Problem
Example: male Type O (ii) x female type AB (IAIB) i IA IB
IAi
IBi
1/2 = IAi
1/2 = IBi
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15. What is it? Co or Incomplete?= +
CODOMINANCE!
Incomplete Dominance

16. Sex-linked Traits Traits (genes) located on the sex chromosomes
Mendelian Genetics
4/6/2019
Sex-linked Traits
Traits (genes) located on the sex chromosomes
Sex chromosomes are X and Y
XX genotype for females
XY genotype for males
Many sex-linked traits carried on X chromosome
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17. Human Diploids have 46 Chromosomes, arranged in pairs
Human Diploids have 46 Chromosomes, arranged in pairs. The last pair determines the individual’s sex.

18. Sex-linked Traits Example: Eye color in fruit flies Sex Chromosomes
Mendelian Genetics
4/6/2019
Sex-linked Traits
Example: Eye color in fruit flies
Sex Chromosomes
XX chromosome - female
Xy chromosome - male
fruit fly
eye color
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19. Sex-linked Trait Problem
Mendelian Genetics
4/6/2019
Sex-linked Trait Problem
Example: Eye color in fruit flies
(red-eyed male) x (white-eyed female) XRY x XrXr
Remember: the Y chromosome in males does not carry traits.
RR = red eyed
Rr = red eyed
rr = white eyed
XY = male
XX = female XR Xr Y
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20. Sex-linked Trait Solution:
Mendelian Genetics
4/6/2019
Sex-linked Trait Solution: XR Xr Y
50% red eyed female
50% white eyed male
XR Xr
Xr Y
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21. Mendelian Genetics
4/6/2019
Female Carriers
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22. Genetic Practice Problems
Mendelian Genetics
4/6/2019
Genetic Practice Problems
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23. Breed the P1 generation tall (TT) x dwarf (tt) pea plants t T
Mendelian Genetics
4/6/2019
Breed the P1 generation
tall (TT) x dwarf (tt) pea plants t T
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24. Solution: tall (TT) vs. dwarf (tt) pea plants t produces the Tt T
Mendelian Genetics
4/6/2019
Solution:
tall (TT) vs. dwarf (tt) pea plants T t
All Tt = tall
(heterozygous tall)
produces the
F1 generation Tt
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25. Breed the F1 generation tall (Tt) vs. tall (Tt) pea plants T t T t
Mendelian Genetics
4/6/2019
Breed the F1 generation
tall (Tt) vs. tall (Tt) pea plants T t T t
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26. Solution: tall (Tt) x tall (Tt) pea plants T t TT Tt tt produces the
Mendelian Genetics
4/6/2019
Solution:
tall (Tt) x tall (Tt) pea plants T t
produces the
F2 generation
1/4 (25%) = TT
1/2 (50%) = Tt
1/4 (25%) = tt
1:2:1 genotype
3:1 phenotype TT Tt tt
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