1. Human Genetics
Genetic
Experiment 626

3. Karyotyping:
technique for examining the chromosome make up of an organism
shows chromosomes arranged by size:
homogulous pairs
a way of detecting abnormalities

4. Karyotyping: chromosomes paired Total of 46 chromosomes Or 23 pair:
22 autosomes, somatic cells, body cells &
1 pair of sex chromosomes
XX = female
XY = male

6. Genes located on the sex chromosomes:
Sex- Linkage:
Genes located on the sex chromosomes:
genes found on the x chromosome = x linked
genes found on the
y chromosome = y linked
a gene found on either the x or y chromosomes = sex linked

7. STOP!!! CK POINT!! Topic: Intro to Human Genetics
Identify the following:
What is/are:
Karyotypes
Sex- linked traits

8. Mutations: any change in the genetic hereditary material of the cell
2 forms:
inheritable mutations – occur in the sex cells
non inheritable mutations – occur in the somatic cells (autosomes, body cells)

9. 2 Types of inheritable mutations:
ADD TO YOUR NOTES!!
Chromosomal Mutations
And
2. Gene mutations

10. What are the 2 types of inheritable mutations?
STOP!!! CK POINT!!
Topic: Mutations 1
What is a mutation?
What are the 2 types of inheritable mutations?

11. Chromosomal Mutations:
change in the structure of a chromosome
the loss of an entire chromosome or addition of a chromosome
Examples Include:
a. Nondisjunction

12. Chromosome Mutation Cont.
A. Nondisjunction:
failure of chromosomes to separate during meiosis
ex. Down syndrome – extra chromosome # 21
Ex .trisomy 18, trisomy 13

13. Nondisjunction:

14. Nondisjunction Down syndrome (trisomy 21):

15. Nondisjunction: Patau syndrome (trisomy 13):
serious eye, brain, circulatory defects as well as cleft palate. 1:5000 live births. Children rarely live more than a few months.

17. Nondisjunction Edward's syndrome (trisomy 18):
almost every organ system affected Children rarely live more than a few months.

19. Other Examples of Nondisjunction: Sex chromosome :
Sex chromosome aneuploids
XO = Turners Syndrome
XXY = Klinefelter Syndrome
XXX = Triplo-X Syndrome
XYY =Jacob Syndrome

20. Turners Syndrome:
XO individuals are genetically female, however, they do not mature sexually during puberty and are sterile. Short stature and normal intelligence. (98% die before birth)

21. XXY = Klinefelter Syndrome
Male sex organs; unusually small testes, sterile. Breast enlargement and other feminine body characteristics. Normal intelligence.

22. XXX = Triplo-X Syndrome
XXX females. 1:1000 live births - healthy and fertile - cannot be distinguished from normal female except by karyotype

23. STOP!!! CK POINT!! Topic: Nondisjunction What is Nondisjunction?
When does it occur? ( Be Specific)
Identify 3 genetic mutations resulting from nondisjunction.
What is the cause for each?

24. Chromosome mutations (structure):
translocation –
a section of
one chromosome is
transferred to a nonhomogulous chromosome
addition – a portion of a chromosome is added

25. Chromosome mutations (structure):
deletion – a portion of a chromosome is deleted
Cri-du-Chat Syndrome (segmental deletion)
inversion – order of genes on a chromosome is changed

26. Chromosomal mutation- Deletion:
Example - Cri du
chat (cry of the cat):
A deletion of a small
portion of
chromosome 5;
these children have
severe mental
retardation, a small
head with unusual
facial features, and
a cry that sounds like a distressed cat.

28. In summary Chromosomal Mutations:
Chromosomal abnormalities can cause serious mental or physical disabilities,
Structure of the chromosome has been compromised
The number of chromosomes is incorrect

29. STOP!!! CK POINT!! Topic: Mutations 2
1. Identify 4 structural chromosomal mutations.
How are each of the 4 chromosomes mutated?
3. What is Turners Syndrome?

30. Gene Mutations
Point Mutation – the substitution, addition, or removal of a single nucleotide
substitutions, 1 nucleotide in a codon is replaced with a different nucleotide, resulting in a new codon.
sickle cell anemia (also called sickle cell disease) is a point mutation substituting Adenine for Thymine in a single DNA codon,

31. Gene Mutations Cont.
Frame Shift Mutation -the addition or deletion of a single nucleotide causes the remaining codons to be incorrectly grouped
Addition/removal – a single nucleotide is added or removed
Addition and Deletion Mutations

32. sickle cell

33. Welcome to Discovery Education Player

34. Characteristics of Mutations:
most are harmful to the organism
they are random
most are recessive traits
Can be beneficial to the organism when the mutation helps the organism to adapt to the environment.

35. Mutagenic Agents:
radiation - x-rays, radioactive isotopes, cosmic rays, ultraviolet rays
chemicals – saccharin, nitrates, carcinogens

36. Human Genetic Traits & Disorders X- linked Traits:
traits controlled by the female sex chromosome
symbolized by a character on 1 of the chromosomes
XX’ X’ carries the trait
The female = the carrier
The trait is not visible in the female

37. Examples of Sex linked traits: X- linked
Ex. Hemophilia –blood disorder in which blood does not clot properly
Ex. Color blindness – cannot distinguish between red and green

42. X-linked traits cont.
Symbols for constructing a Punnett square (sex-linked trait)
XX normal female
XY normal male
X’X carrier female
X’Y male with hemophilia
Know These!!!!

43. Ex. Hemophilia
Hemophiliac male x carrier female
Genotype
Phenotype

44. Hemophilia cont.
Normal male x female carrier
Genotype
Phenotype

45. 2 or more alleles for a particular trait
Multiple Alleles:
2 or more alleles for a particular trait
alleles are expressed as codominant
ex. Blood types

46. Human Blood Types: Phenotype Genotype A IAIA, IAi B IBIB, IBi AB AB
O ii

47. Blood Types & Punnett Squares;
What are the
possible outcomes
for a heterozygous
A blood type
crossing
with a homozygous
B blood type?
Genotypes
Phenotypes

48. Blood Type Cont. Construct a punnett square showing a
cross b/w a blood type O person with a
heterozygous B blood type person
Genotype
Phenotype

49. Why?
THINK!
Raise your hand to answer…
WHY Blood typing important?

50. RBC

51. agglutination

52. Put your skills to the test!
Look at the handout provided:
“Using Blood tests
to Identify Babies”

53. Polygenic Traits: traits controlled by 2 or more alleles
expressed as incomplete dominance
ex. Eye color, height, and skin color
This pattern of inheritance is identified has a wide range of phenotypes (skin & hair color).

54. How is multiple alleles different from polygenic traits? (look in your
THINK…
How is multiple alleles different from polygenic traits? (look in your
notes!)

57. Go SU!!

59. Genetic Disorders:
Genetic screening or studying Karyotypes can show possible genetic disorders
Amniocentesis – Karyotyping and analyzing amniotic fluid for fetal cells
Chorionic villi sampling – piece of the placenta that is studied for genetic abnormalities
Ex. PKU: a genetic disorder that does not allow the baby to breakdown phenylalanine , can cause severe brain damage
Can be detected and eliminated with special diets

63. STOP!!! CK POINT!! Topic: Genetic Disorders
What is the difference among:
Multiple Alleles
Sex-Linked Traits
Polygenic Traits
What is amniocentesis?

64. Disorders associated with Genetics:
Cystic Fibrosis
Tay - Sacs Disease
Phenylketonuria (PKU)
Huntington’s disease
Albinism

65. Cystic Fibrosis Symptoms Mucous clogs the lungs and pancreas
Usually do not survive into adulthood
White population most effected

66. Tay-Sachs Symptoms: Deterioration of the nervous system
Usually do not survive adulthood
European descents most effected

67. Failure of the brain to develop during infancy
PKU
Failure of the brain to develop during infancy
If untreated, death in early childhood
Controlled by diet!!

68. Huntington’s Disease Carried on an autosome (Dom) Symptoms:
Forgetfulness
Appears in 30’s-40’s
Loss of muscle control
Uncontrollable muscle spasms
Mental illness
death

69. In your pkt: Get into your groups: > 1 min. Get owl text books
Same place as yesterday
Turn to pg 91-92
Begin answering questions
Popsicle sticks!!