1. Heredity

2. Your Physical Appearance
Heredity is the passing of traits from parents to an offspring.
Gregor Mendel was the first scientist to successfully study inheritance
He is the “Father of Genetics”

3. Why Pea Plants? Mendel use Garden Pea Plants for his research because:
They grow quickly
They naturally self-pollinate

4. Mendel’s Success
Mendel was successful with his pea plant research because:
he studied one trait at a time! (independent variable)
He had studied statistics
*A trait is a distinct phenotypic characteristic that may be inherited

5. Pea Plant Traits Flower Color Flower Position Seed Color Seed Shape
Pod Shape
Pod Color
Plant Height

6. The Experiment
Mendel began by taking pure trait plants and cross-pollinating them
He did this by hand, not with bees!

7. The Experiment Part I (Example 1)
Plant height
Mendel crossed a Tall parent plant with a short parent plant:
Tall x short = All Tall
TT x tt = Tt
parent x parent = First Filial (F1)

8. The Experiment Part I (Example 2)
Flower Color
Mendel crossed a Purple parent plant with a white parent plant:
Purple x white = All Purple
PP x pp = Pp
parent x parent = First Filial (F1)

9. The Experiment Part II
He wondered why one trait disappeared when he crossed the two pure plants
He decided to allow the new F1 plants to naturally self-pollinate and here is what he found……..

10. Example 1- Plant Height F1 Tall plants self-pollinate and produce:
25% short plants

11. Example 2 - Flower Color F1 Purple Flower color plants
self-pollinate and produce:
75% Purple flowers
25% white flowers

12. Mendel’s Conclusion
The Principle of Dominance and Recessiveness states that one trait is more likely to occur than the other.
Dominant is a trait that is most likely to occur
Recessive is a trait that is usually hidden in the first generation, but may reappear later

13. Probability
The chance or possibility that a certain outcome will occur. Usually written as:
Fractions
Decimals

14. Let’s Learn a New Language..
Genotype- the genetic make-up of an organism (TT, Tt, tt)
Phenotype- the physical appearance of an organim (Tall, short, Purple, white)
Dominant- more likely to occur (The tall plants or the purple flowers)
Recessive- less likely to occur (The short plants or the white flowers)

15. Let’s Learn a New Language..
Homozygous- when both alleles are the SAME
Homozygous Dominant: TT, PP, WW
Homozygous Recessive: tt, pp, ww
Heterozygous- when each allele is DIFFERENT
Tt, Pp, Ww

16. Let’s Learn a New Language..
An Allele is an alternate form of a gene; one part of a pair
A Gene is composed of two alleles, one from each parent
Allele Allele = Gene
T(mom) t(dad) = Tt(child)

18. Punnett Squares
Developed by Rudolph Punnett to make genetics easier for us to understand

19. Genetics Example 1
In garden pea plants, tall plants are dominant (T) and short plants are recessive (t). A pea plant that is homozygous dominant for height is crossed with one that is homozygous recessive for plant height.
Draw a Punnett square to represent the problem.
What are the possible genotypes?
What are the possible phenotypes?
What is the probability of each genotype?
What is the probability of each phenotype?

20. Genotypes
Phenotypes
Probability of genotypes
Probability of phenotypes

21. Genetics Example 2
In garden pea plants, purple flower color (P) is dominant over white flower color (p). A pea plant that is homozygous recesive for flower color is crossed with one that is heterozygous for flower color.
Draw a Punnett square to represent the problem.
What are the possible genotypes?
What are the possible phenotypes?
What is the probability of each genotype?
What is the probability of each phenotype?

22. Genotypes
Phenotypes
Probability of genotypes
Probability of phenotypes

23. Genetics Examples
In garden pea plants, yellow seeds (Y) are dominant and green seeds (y) are recessive. What offspring would result if two heterozygous plants were crossed?
Draw a Punnett square to represent the problem.
What are the possible genotypes?
What are the possible phenotypes?
What is the probability of each genotype?
What is the probability of each phenotype?

24. Genotypes
Phenotypes
Probability of genotypes
Probability of phenotypes

25. More Genetics

26. Incomplete Dominance
Sometimes one trait is not completely dominant over the other
The same letter allele is used
Red x White = Pink
RR x R’R’ = RR’
This results with a combined genotype
Snap dragons

27. Codominance Sometimes both traits are equally dominant
Different letter alleles are used
Black x White = Checkered
BB x WW = BW
This results in both traits being expressed
Checkered Chickens

28. Alternate forms of Genetics
Gregor Mendel studied simple genetic inheritance:
Offspring were either dominant or recessive
But not all traits are simple!!

29. Thomas Hunt Morgan Studied Fruit Flies Discovered Gender inheritance
Other traits associated with gender

30. Gender
Gender is always determined by the male

31. Sex-linked Traits Some traits are only located on the “X” chromosome
Since Males only have one “x” chromosome, they are more likely to show the trait than a female with two “x” chromosomes

32. Sex-linked Traits
Colorblindness
Hemophilia
Muscular dystrophy

33. Other Types of Inheritance
Insert chart here

34. Meiosis
Meiosis is the formation of gametes in sexually reproducing organisms
Sperm (male)
Egg (female)

35. Benefits of Meiosis Forms gametes (sex cells)
Allows for genetic variation
Reduces the number of chromosomes by half
Human body cells 46 chromosome
Human sex cells 23 chromosome
Allows the chromosome number of any organism to remain consistent

36. Haploid vs Diploid
Haploid cells contain 1 set of chromosomes (23 total in humans)
Sperm
Egg
Diploid cells contain 2 sets of chromosomes (46 total in humans)
One set from mom
One set from dad

37. Meiosis

38. Male vs Female Meiosis

39. Karyotype
A karyotype is a picture of someone’s
chromosomes

40. Male Karyotype

41. Female Karyotype

42. What do you think?

43. Genetic Disorders Genetic disorders are caused by mutations in DNA
Mutations that occur spontaneously
Congenital ( people are born with them)
Unable to cure
Can occur in children even when parents do not have them (recessive traits)

44. Genetic Counselors
Genetic counselors are available for people who fear passing genetic disorders to their offspring
Cystic fibrosis
Sickle-cell anemia
Huntington’s disease
Down’s syndrome
Many others
They begin with making a pedigree to observe the family history of traits

45. Pedigree
A pedigree is a map of a family genetic history

46. Selective Breeding Genetic Engineering
Genetics in Action
Selective Breeding
Genetic Engineering

47. Genetics Terminology
Purebred organisms result from crossing two organims with similar traits
Hybrids are produced when two organisms with different traits are combined

48. Purebred Advantages Disadvantages Predictable outcome
Example:
Dog breeds
Lab x Lab = Lab
LL x LL = LL
Disadvantages
Undesirable traits are possible
A lack of genetic variation will result

49. Hybrids Advantages Disadvantage Variety of traits may appear
Can encourage desirable traits to occur
Example:
kiwi x strawberry = kiwiberry
Disadvantage
Unpredictable outcomes are likely

50. Selective Breeding
Selective breeding involves the crossing of organisms with desired traits to maximize their potential
Fruits
Vegetables
Flowers
Livestock
Insulin

51. Genetic Engineering A faster form of selective breeding
Genetic engineering is when genetic information is changed within the DNA of an organism