1. Do Now
List several things you believe you genetically inherited from your parents.
List some things about you that you don’t think you have inherited genetically.

2. Heredity Heredity is the passing of traits from parent to offspring.
The different forms a gene may have for a trait are its alleles.
Each parent has 2 alleles.
Alleles are then passed to the offspring

3. Heredity
The alleles control what trait will show up in the offspring.
While one allele may control the trait that shows, the other may control an alternate form of the trait.
The study of how these
Traits are passed on is called
GENETICS.

4. Who Discovered Genetics??? Dominant / Recessive
Gregor Mendel (father of Genetics)
Austrian monk, discovered by studying pea plants, he was able to predict what the offspring would look like based on the parent plants.

5. Gregor Mendel pea plants
The following are traits that mendel looked at in his plants.
Dominant – the stronger trait, covers up the weaker trait.
Represented by a Capital letter T
Recessive – The weak trait. Seems to disappear.
Represented by a lower case letter t
Dominate Recessive

6. Genotype Genotype is the genetic makeup of an organism.
Genotype is represented by the 2 letters in a parent’s or offspring’s alleles. (TT, tt, Tt)
An organism with 2 alleles that are exactly the same (TT or tt) is called HOMOZYGOUS (Pure).
An organism with 2 alleles that are different (Tt) is called HETEROZYGOUS (Hybrid)

7. Phenotype
Phenotype is the physical expression of a particular genotype
The way it looks.
Ex. If (F) = FAT, (f) = skinny. What are the 3 possible genotypes?
FF, Ff, and ff
Phenotypes
Homozygous FAT
Hetrozygous FAT
Homozygous skinny

8. Practice genotype / Phenotype
Genotype Phenotype TT = Homozygous Tall tt = Homozygous short Tt = Heterozygous Tall SS = Homozygous smooth ss = Homozygous rough Ss = Heterozygous smooth RR = Homozygous round rr = Homozygous oval Rr = Heterozygous round
KEY
T = Tall
t = short
S = smooth
s = rough
R = round
r = oval
Can there ever be heterozygous for short (tT)???
NO!! The dominant trait will ALWAYS cover up the recessive trait.

9. How did Mendel predict the offspring??
Mendel used a prediction tool call the PUNNETT SQUARE.
Punnett squares help you keep track of traits.
To find out the traits of the offspring, you need 2 parents to mate. T t
T t

10. Do Now
Define Genotype
Define Phenotype

11. Crossing the two parents
T = Tall, t = short
Parent 1 = Tt, Parent 2 = Tt
Tt x Tt
Genotype of Parent 1 = Tt
Phenotype of parent 1 = Tall
Genotype of Parent 2 = Tt
Phenotype of parent 2 = Tall
Offspring
Genotypes of offspring = TT, Tt, tt
Phenotypes of offspring = Tall and short
T t T t

12. You Try One!! S = Smooth, s = rough Parent 1 = SS, Parent 2 = Ss
SS x Ss
Genotype of Parent 1 =
Phenotype of parent 1 =
Genotype of Parent 2 =
Phenotype of parent 2 =
Offspring
Genotypes of offspring =
Phenotypes of offspring =
S S S s

13. Try another!! S = Smooth, s = rough Parent 1 = ss, Parent 2 = Ss
ss x Ss
Genotype of Parent 1 =
Phenotype of parent 1 =
Genotype of Parent 2 =
Phenotype of parent 2 =
Offspring
Genotypes of offspring =
Phenotypes of offspring =
s s S s

14. And another!!!! R = Round, r = oval Parent 1 = RR, Parent 2 = rr
RR x rr
Genotype of Parent 1 =
Phenotype of parent 1 =
Genotype of Parent 2 =
Phenotype of parent 2 =
Offspring
Genotypes of offspring =
Phenotypes of offspring =
R R r

15. Do Now G= Green hair, g= blue hair
Complete a Punnett square crossing someone with blue hair and someone heterozygous for green hair. Include the genotypes/phenotypes of the offspring with percentages.

16. Incomplete Dominance
When 2 PURE parents are crossed, they produce an intermediate (in the middle) phenotype.
Japanese 4 o’ clock
Red x white = Pink

17. Cross a Red J 4 o’c with a White J 4 o’c
Incomplete Dominance
Both colors are dominant
RR = Red
WW = White
Cross a Red J 4 o’c with a White J 4 o’c
R R
Offspring
Genotypes of offspring =
Phenotypes of offspring = W

18. Incomplete Dominance Cross a Red J 4 0’c with a Pink J 4 o’c Offspring
Genotypes of offspring =
Phenotypes of offspring =

19. Sex determination The man controls the sex of offspring
Men contain the X and Y chromosomes (XY)
Women contain two X chromosomes
Cross a male (XY) and female (XX)
Offspring
Genotypes:
Phenotypes:

20. Sex – Linked / X-linked Genes
An allele inherited on a sex gene.
Some conditions are inherited on the X or Y chromosome.
Ex. Colorblindness, hemophilia
X-Linked means the trait only shows up on the X chromosome. (X )
c = gene for colorblindness
All X chromosomes must carry X to be colorblind. c c

21. Sex – Linked / X-linked Genesc
X Y = Male colorblind
X X = Female carrier
Cross a male colorblind with a female carrier c
Offspring
Genotypes of offspring =
Phenotypes of offspring =

22. Do Now
Explain why the odds of having a boy/girl are 50:50

23. Blood Typing = Multiple alleles Co-Dominance
Many traits controlled by more than 2 alleles.
Can you list the different blood types?
Genotype Phenotype
AA Type A
BB Type B
AB Type AB
oo Type O
Ao Type A
Bo Type B
A and B are both dominant, Type AB = Universal recievers
O is recessive Type OO = Universal givers

24. Blood Typing = Multiple alleles
Cross blood type AO with blood type BO
Offspring
Genotypes of offspring =
Phenotypes of offspring =

25. A family history of a genetic condition
PEDIGREE CHARTS
A family history of a genetic condition

26. Blood Typing = Multiple alleles
DO NOW Cross blood type AB with blood type BB
Offspring
Genotypes of offspring =
Phenotypes of offspring =

27. What is a pedigree chart?
Pedigree charts show a record of the family of an individual
They can be used to study the transmission of a hereditary condition
They are particularly useful when there are large families and a good family record over several generations.

28. Symbols used in pedigree charts
A marriage with five children, two daughters and three sons. The middle son is affected by the condition.
Eldest child  Youngest child
Normal male
Affected male
Normal female
Affected female
Marriage

29. Example of Pedigree Charts
Dominant or Recessive?
Is this pedigree dominant or recessive?

30. Answer
Dominant
It is dominant because a parent in every generation have the disorder. Remember if a parent in every generation has the disorder, the disorder has not skipped a generation. If the disorder has not skipped a generation the disorder is dominant.

31. Example of Pedigree Charts
Dominant or Recessive?
Is this pedigree dominant or recessive?

32. Answer
Recessive
It is recessive because a parent in every generation does not have the disorder. Remember the disorder can skipped a generation if the disorder is recessive. The parents can be heterozygous and be carriers of the disorder but not have the symptoms of the disorder.