1. Do Now!!  True or False?
1. Certain thoughts or experiences of a mother mark or alter the hereditary makeup of an unborn child.
2. Color blindness is more common in males than in females.
3. A person may transmit characteristics to offspring which he/she does not show.
4. Certain inherited traits may be altered by the stars, planets or moon early in development.
5. The total number of male births exceeds female births each year.

2. Allele: Version of a gene Dominant: shields recessive trait
(ex: B=brown eyes)
Recessive: masked by dominant
(ex: b=blue eyes)
Heterozygous: 2 different alleles
(ex: Bb)
Homozygous: 2 of the same alleles
(ex: BB, bb)
Genotype: organism’s set of genes
(ex: BB, Bb, bb)
Phenotype: physical appearance
(ex: brown or blue eyes)

4. Chapter 10: Genetics!

5. Objectives To distinguish between heredity and inheritance
To describe Mendel’s experiments in heredity
To compare heterozygous vs. homozygous and dominant vs. recessive.

6. Do Now!! 
Ariel and Prince Eric are curious to see what their babies will look like! Eric is heterozygous for black hair and Ariel has the recessive trait of red hair. Both are recessive for blue eyes. If they have 32 children, how many can we EXPECT to have red hair and blue eyes?

7. Do Now!! 
Mickey Mouse is heterozygous for round ears and homozygous for black eyes. Minnie Mouse is homozygous for floppy ears and heterozygous for black eyes. Determine phenotype ratios.

8. Genetics: the study of heredity by which traits are passed from parents to offspring

9. Gregor Mendel The father of genetics!
First to develop rules that accurately predict patterns of heredity
Discovered how traits were inherited in a population using pea plants

10. The beginning of genetics…
The passing of traits to the next generation – inheritance or heredity
Mendel performed cross-pollination and self-fertilization in pea plants
Mendel followed various traits in the pea plants he bred

11. 7 Traits Mendel Studied

12. Pollination: transfer of pollen from anthers to stigma in flowers
1) self pollination occurs within the same flower or same plant
2) cross pollination occurs between different plants

13. Mendel’s Crosses with Pea PlantsX
Pure tall
plants
Pure short
plants
parental
generation P1
Cross Pollination
first filial
generation
All Tall plants F1
Self Pollination
second filial
generation
787 tall plants, 277 short plants F2
3 to ratio

14. Generations P Generation Parents Pure bred F1 Generation
Hybrid – 2 different types of genes for a trait
F2 Generation
3:1 ratio

17. Mendel’s 3 Laws of Inheritance
Law of Dominance- Each trait is controlled by 2 factors:
Dominant- what is expressed
Recessive- masked in presence of dominant P1 F1 F2

18. Mendel’s 3 Laws of Inheritance (cont.)
2. Law of Segregation- Each allele separates into different gametes (when does this happen??)
Ex. Ww – one W goes in one sperm and the other w goes into another sperm Ww w W

19. Mendel’s 3 Laws of Inheritance (cont.)
3. Law of Independent Assortment- Gene pairs (homologous) will separate randomly into gametes during meiosis
*Chromosomes line up randomly at metaphase plate

20. Do Now!!  (P. 6)
What were the results of Mendel’s experiments for F1 and F2 generations?
What are his 3 laws?
What is a gene?

21. Definitions *genes occur in pairs
Gene – segment of DNA on a chromosome that codes for a particular protein
*genes occur in pairs

22. Allele – alternative form of a gene
Dominant capital letter (shields recessive trait)
T = tall
t = short
G = green
pods
g = yellow
pods
Recessive Lowercase letter (usually hidden)

23. More alleles!

24. Phenotype – physical characteristics of an organism
(Ex: Blue eyes or Brown Eyes)

25. Genotype -genetic makeup of an organism (genes) -alleles received from parents
(internal information Ex: BB, Bb, bb)

26. Genotype vs. Phenotype TT
Tall
genotype
phenotype

27. Homozygous – when both alleles of a pair are the same
dominant TT
homozygous
recessive tt

28. Heterozygous – when both alleles of a pair are not the same
(tall) Tt

29. for black hair… (H=Black, h=blonde) 1. What is Jon Snow’s genotype?
If Jon Snow is heterozygous
for black hair… (H=Black, h=blonde)
1. What is Jon Snow’s genotype?
2. What is Jon Snow’s phenotype?
Beyonce is BB. (B= brown eyes, b=blue eyes)
1. What is her genotype?
2. What is her phenotype?
3. Is she heterozygous or homozygous? Explain.

30. Genotypic vs. Phenotypic Ratios
Phenotype Ratio:
Ratio of different physical traits
Ex) Brown eyes ¼ or 25%
Genotype Ratio:
Ratio of the different possible alleles
Ex) Tt = ¼ or 25%

31. Monohybrid Cross R= Can roll your tongue r= Can’t roll your tongue
Genotype Ratio:
Phenotype Ratio: R r

32. Lets Try a Monohybrid together!
Daffy Duck is heterozygous for black feathers. Daisy Duck is homozygous for yellow feathers. Set up a punnett square and determine probabilities of their potential offspring. (Both genotype and phenotype ratios!)
B = Black b = yellow

33. DO NOW!! 
Sleeping Beauty has freckles. Her prince charming is heterozygous for no freckles. What are the chances of her children having freckles? Please show your work.

34. Test cross – an individual with unknown genotype is crossed with a homozygous recessive individual
used to determine the genotype of any individual whose phenotype is dominant

35. Lets Try a Test Cross
Spongebob squarepants doesn’t know whether or not he is Homozygous Dominant or Heterozygous for his yellow color. The recessive trait is a white sponge. Let’s say that we perform a “test cross” on spongebob (spongebob + a white female sponge) and all of the baby sponges are yellow. What would spongebob’s genotype be?

36. What is a dihybrid Cross?
A dihybrid cross allows us to predict possible outcomes of offspring that will have 2 traits simultaneously.
Ex: what would you get if you crossed a Brown-haired brown-eyed male with a blonde-haired blue-eyed female? How many of the children would have brown hair and brown eyes? Brown hair and blue eyes? Blonde hair and brown eyes? Blonde hair and blue eyes?

37. Setting up Dihybrid Crosses
1. Labels!!
2. Determine parent genotypes
3. Determine gametes (alleles to be passed down)
The FOIL method
4. Set up punnet square
5. Determine outcome
Phenotype Ratio

38. Dihybrid Crosses Looking at two different traits
Ex. Hair color and eye color
B=brown eyes
b=blue eyes
R=Brown hair
r=blonde hair
Mother is heterozygous for both traits
Father is heterozygous for eye color and homozygous dominant for hair color

39. Example

40. More Practice
Mickey Mouse is heterozygous for Round ears and homozygous for Black eyes. Minnie Mouse is homozygous for Floppy ears and heterozygous for Black eyes. Determine phenotype ratios. (B=black eyes, b=brown eyes, R=round, r= floppy.)

41. Gene Linkage There are several genes on a chromosome Gene Linkage:
When two genes are close to each other on the same chromosome

42. Gene Linkage (cont.)
Linked genes on a chromosome results in an exception to Mendel’s law of independent assortment
Linked genes usually do not segregate independently

43. Drosophila melanogaster (Fruit Flies)
First organism with linked genes
Linked genes typically travel together during crossing over

44. Chromosome Map A map of genes on chromosomes
Crossing over occurs more frequently between genes that are far apart

45. Strawberries are octoploid!!
Polyploidy
Cells that contain more than 2 homologous sets of chromosomes
Ex. A triploid organism (3n) - means that it has three complete sets of chromosomes.
Strawberries are octoploid!!

46. Pedigree Shows history of a trait in a family
Allows researchers to analyze traits within a family

47. In a pedigree… You can see how a genetic disorder runs in a family.
Carriers are individuals who are heterozygous for an inherited disorder but do not show symptoms.
Carriers can pass the allele for the disorder to their offspring

48. Symbols for Pedigree

49. Figure out each genotype!

50. Do Now!! 
Fill in the genotypes for the following pedigree (shows recessive trait)
B=brown eyes
b = blue eyes

51. Incomplete dominance Red + White = Pink
Heterozygous phenotype is intermediate between two homozygous phenotypes:
In between two extremes
Heterozygous phenotype appears blended.
Ex: Four O’clock flowers
Red + White = Pink

53. Codominance Both traits are dominant and expressed (no blending)
Ex: Roan Cows
white hair (HW) is codominant with red hair (HR)
cows with genotype (HRHW) have coats with a mixture of red and white hairs (roan)
Red + White = RED AND WHITE

54. Do Now!!  What is the difference between incomplete and codominance?
Cross a roan cow with a red cow.

55. Multiple alleles – 3 or more alleles that control a trait
Example: blood type!
Possible alleles: IA, IB, i
Which genotypes are heterozygous? Homozygous?
GENOTYPES
RESULTING PHENOTYPES
IAIA
IAi
Type A
IBIB
IBi
Type B
IAIB
Type AB ii
Type O

56. Antigens vs. Antibodies
Antigen: substance foreign to the body that causes an immune response:
Can act as surface markers
EX: type A antigens on surface of type A blood cells
Antibody: protein that reacts with specific antigen:
EX: Type B blood contains anti-A antibodies

57. Which is the universal donor? Universal acceptor?

58. Determine Blood Type
Determine the possible offspring of the following crosses
1. AB and O
2. Homozygous A and heterozygous B
3. AB and AB

59. What do you see?

60. What do you see?

61. Sex Linked Traits Traits located on the sex chromosomes (X or Y)
X linked: gene is located on the X chromosomes
Y linked: gene is located on the Y chromosome
Ex: color-blindness is X-linked!
*If X-linked, can males be carriers?

63. Sex-Linked Traits
A man who is color blind marries a woman that is heterozygous for color blindness. What is the chance of having a color blind boy?

64. Polygenic Traits
Polygenic traits arise from the interaction of multiple pairs of genes.