1. Human Traits and Mendelian Genetics

2. Genetic Vocabulary Genetics – Heredity – Traits – Gametes –
The study of inheritance
Heredity –
The passing on of characteristics from parents to offspring
Traits –
Characteristics that are inherited
Gametes –
Sex cells (sperm and egg)

3. Genetic Vocabulary Genotype – Phenotype – Heterozygous – Homozygous –
The genes that you can’t see. (B, b)
Phenotype –
The physical trait that is observed (Black or white)
Heterozygous –
Different (Hh)
Homozygous –
Same (HH)

4. Genetic Vocabulary Dominant – Recessive – Alleles –
a trait that will appear in the offspring if one of the parents contributes it. (Upper case letters)
Recessive –
a trait that must be contributed by both parents in order to appear in the offspring. (Lower case letters)
Alleles –
One member of a pair or series of genes that occupy a specific position on a specific chromosome.

5. DNA is found in your chromosomes.

6. 30,000 genes are inherited in every human.

7. Traits that you inherit

8. Cleft “Butt” Chin

9. Free and Attached Ear Lobes

10. Widow’s Peak

11. Clasping Hands

12. Bent Little Finger

13. Hitch-hikers Thumb

14. Long palmar muscle

15. Mid-digital Hair

16. Eye Shape
Almond shaped eyes
Round shaped eyes

17. Hair on back of hand

18. Freckles

19. Tongue Rolling

20. Tongue Folding

21. Dimples

22. Skin Color

23. Unibrow

24. Baldness

25. P.T.C. Paper
Phenylthiocarbamide, also known as PTC, or phenylthiourea, is an organic compound having the unusual property of either tasting very bitter, or being virtually tasteless, depending on the genetic makeup of the taster. The ability to taste PTC is a dominant genetic trait. The test to determine PTC sensitivity is one of the most common genetic tests on humans.
About 70% of people can taste PTC

26. Mendel and His Pea Plants

27. GREGOR MENDEL The “father” of genetics Lived from 1822-1884
Austrian Monk
Published his work in 1866, but no one took him seriously until 1900.
Studied Pea Plants!

28. MENDEL’S EXPERIMENTS

29. Mendel experimented with 7 different characteristics

30. Mendel Got Lucky for 2 Big Reasons
First, he had a lot of time…he was a monk. This let him do LOTS of experiments with the peas!
Each trait had 2 options. This was key because he could tell if it was one way or the other.

31. Mendel and his laws Law of Segregation Law of Independent Assortment
During fertilization, gametes randomly pair to produce four combinations of alleles
Law of Independent Assortment
Genes for different traits are inherited independently of each other

32. Monohybrid Cross –
Cross of a single trait

35. There are two terms used to describe the genes an organism has compared to what an organism looks like

36. PHENOTYPE physical characteristics (Tall, Brown)

37. GENOTYPE the genetic makeup (TT,Tt)

38. Check For Understanding
Is the following information the PHENOTYPE OR GENOTYPE of an organism.
The Giraffe is spotted
Answer: Phenotype

39. How can we determine what the offspring are going to be?

40. PUNNETT SQUARES

41. PUNNETT SQUARES show the possible combination of alleles in a cross

42. Punnett Squares show the probability of getting a certain type of offspring

43. THE PARENTS GENOTYPES DAD = Tt (heterozygous) MOM = Tt (heterozygous)
PHENOTYPES
DAD = Tall
MOM = Tall

44. PUNNETT SQUARES T t T T T T t T t t t t

45. THE OFFSPRING GENOTYPES 1TT:2Tt:1tt (1:2:1) TT (homozygous dominant)
Tt (heterozygous)
tt (homozygous recessive)

46. What are the PHENOTYPES?
THE OFFSPRING
What are the PHENOTYPES?
3 Tall: 1Short
TT (tall)
Tt (tall)
tt (short)

47. Cross a heterozygote with another heterozygote (for hair color where Black is B, b = blonde). Find the genotype and the phenotype

48. B b B B B B b B b b b b

49. THE OFFSPRING GENOTYPES 1BB:2Bb:1bb (1:2:1) BB (homozygous dominant)
Bb (heterozygous)
bb (homozygous recessive)

50. THE OFFSPRING PHENOTYPES 3 Brown :1 Blonde (3:1) BB (Brown) Bb (Brown)
bb (Blonde)

51. Cross a dominant homozygote with a heterozygote (for nose size where big nose is N and small nose is n). Find the genotype and the phenotype

52. N N N N N N N N N n n n

53. Albinism

54. PRACTICE!

55. 1. Cross a homozygous dominant with a homozygous recessive (for height where T is dominant and tall). Find the genotype(s) and the phenotype(s)

56. 2. Cross a heterozygote with a recessive (for height where T is dominant and tall). Find the genotype(s) and the phenotype(s)

57. 3. Cross a heterozygote with another heterozygote (for skin color where Black is B, b = white). Find the genotype(s) and the phenotype(s)