1. Natiwya Saddler Mitchell Loll

2. Background Info Genotype: the alleles of an organism
Phenotype: all characteristics of an organism
Punnett Square: means of finding the expected ratio of the offspring, given certain parental phenotypes
Monohybrid: cross of parents that are homozygous except for a single gene locus that has two alleles (RR and rr)

3. Cont.
Allele: member of a pair or series of genes that occupy a specific position on a specific chromosome
Homozygous: having the same alleles at a particular gene locus on homologous chromosomes
Heterozygous: having different alleles at on or more corresponding chromosomal loci.
Locus: position a gene occupies on a chromosome

4. 4.3.2
Determine the genotypes and phenotypes of the offspring of a monohybrid cross using a Punnett Grid

5. What is a Punnett Square?
Created in early 1900’s by Reginald Punnett
depicts the number and variety of genetic combinations
All possible offspring of two parents
for each gene

6. 4.3.3
State that some genes have more than two alleles (multiple alleles).
Multiple Alleles: When more than two alleles control a trait these are known as multiple alleles.

7. 4.3.4
Describe ABO blood groups as an example of co-dominance and multiple alleles

8. Co-Dominance: Situation in which two different alleles for a genetic trait are both expressed
Red plant +
White plant =

9. 4.3.5
Explain how the sex chromosomes control gender by referring to the inheritance of X and Y chromosomes in humans
Both males and females have X
Only males have Y
Receive Y from your dad
½ chance of being male

10. 4.3.6
State that some genes are present on the X chromosome and absent from the shorter Y chromosome in humans
X chromosome is much larger
X-linked genes only appear on X chromosome
Colorblindness
Hemophilia
More common in males

11. 4.3.7
Define Sex Linkage
Sex Linkage: the phenotypic expression of an allele that is dependent on the gender of the individual
directly tied to the sex chromosomes.
Occurs when genes carried on sex chromosomes
Most often on X chromosome

13. 4.3.8
Describe the inheritance of color blindness and hemophilia as examples of sex linkage
Both most common in males
Produced by recessive sex-linked allele on X chromosome
½ of males receive
colorblindness

14. 4.3.9
State that a human female can be homozygous or heterozygous with respect to sex linked genes
Females have two X chromosomes
Homozygous: both alleles are the same
Dominant or Recessive
Heterozygous: different alleles.
One dominant, one recessive

15. Males have only one X chromosome
Homozygous and heterozygous do not apply

16. 4.3.10
Explain that female carriers are heterozygous for X-linked recessive alleles
Woman can carry traits without being effected
Men have one chromosome, one allele will be expressed

17. This mother was a carrier for hemophilia but was not effected by the condition.
Half of her sons will carry have hemophilia
Y chromosome carries no allele

18. 4.3.11
Predict the genotypic and phenotypic ratios of offspring of monohybrid crosses involving any of the above patterns of inheritance
¼ = GG Homozygous Dominant
½ = Gg Heterozygous
¼ = gg Homozygous Recessive

19. Practice
Punnett Square One
Height in plants
T=tall
T=short T t

20. ½ Homozygous Dominant
½ Heterozygous T TT t Tt

21. Genotype: ½ Homozygous Dominant ½ Heterozygous
Phenotype: 100% Tall Plant

22. Punnett Square Two
Eye Color in Humans
B= Brown
b= Blue B b

23. Punnett Square Two
Eye Color in Humans B b BB Bb bb

24. Genotype: ¼ Homozygous Dominant ¼ Homozygous Recessive ½ Heterozygous
Phenotype: ¾ Brown eyes ¼ Blue eyes

25. Punnett Square Three
Hair
C= Curly Hair
B= Bald b C

26. b C Cb bb

27. Genotype: ½ Heterozygous ½ Homozygous Recessive
Phenotype: ½ Curly Hair ½ Bald

28. Punnett Square Four
Dwarfism
D= dwarf
N= normal proportion D n

29. D n Dn nn

30. Genotype: ½ Heterozygous ½ Homozygous Recessive
Phenotype: ½ Dwarf ½ Normal Proportion

31. Punnett Square Five
Blood Type A B o

32. Punnett Square Five
Blood Type A B AA AB o

33. Genotype: ½ A blood ¼ AB blood ¼ B blood
Phenotype: ½ A blood ¼ AB blood ¼ B blood