1. Pedigrees, karyotypes, and genetic disorders
CLE Compare different modes of inheritance: sex linkage, co-dominance, incomplete dominance, multiple alleles, and polygenic traits.
CLE Describe the connection between mutations and human genetic disorders.

2. Overview Review karyotypes and chromosome type
Discuss mutations and various genetic disorders
Compare these with sex-linked inheritance
Apply the use of karyotypes and pedigrees to better understand inheritance

3. Karyotypes
A karyotype is an organized profile of an individual’s chromosomes. In a karyotype, chromosomes are arranged and numbered by size, from largest to smallest.
Humans have 46 chromosomes or 23 pairs.
22 of these pairs are autosomes.
1 pair are sex chromosomes, X and Y.
Which chromsomes do females have? Males?

4. Normal Karyotype
Autosomes
(44) 
 Sex chromosomes (2)

5. *3 Chromosomes instead of 2
Abnormal Karyotype
Autosomes
(44) 
 Sex chromosomes (2)
*3 Chromosomes instead of 2

6. KINDS OF MUTATIONS Mutations that produce changes in a single gene =
Images from:
KINDS OF MUTATIONS
Mutations that produce changes
in a single gene =
_________________
in whole chromosomes = _____________________
GENE MUTATIONS
CHROMOSOMAL MUTATIONS

7. KINDS OF MUTATIONS BODY SOMATIC ________ CELLS = ___________ CELLS
Somatic cell mutations can: ______________________
______________________
_____________
Cause cancer
Make cell not able to function
Kill cell
BUT _________ passed on to offspring
WON’T BE

8. Kinds of Mutations ___________ = _________cells (sperm & eggs) GAMETES
GERM
Germ cell mutations ________ passed on to offspring
CAN BE

9. Many genetic ___________ result from
MANY HUMAN GENES HAVE BECOME KNOWN THROUGH THE STUDY OF GENETIC DISORDERS
Many genetic ___________ result from
changes in the DNA code so _________________ proteins are produced.
DISORDERS
NON-FUNCTIONING

10. What do I need to know about each disorder?
Which specific type of disorder it is:
Autosomal Recessive
Autosomal Dominant
Sex-Linked
Nondisjunction
Codominant
What causes it
Characteristics of it

11. Autosomal Recessive Disorders
Example: Albinism:
AA = no albinism
Aa = carrier for albinism
aa = albino
A mutation that creates a disfunctional protein that appears RECESSIVE to the working allele.
Includes:
Albinism
Cystic Fibrosis
Phenylketonuria (PKU)
Tay-Sach’s disease
Sickle-cell disease

12. Autosomal Recessive Disorders
Albinism
Characterized by lack of pigment in the skin, hair, and eyes.

13. Albinism

14. Autosomal recessive: CYSTIC FIBROSIS
CAUSE: Loss of 3 DNA bases in a gene for the _____________ that transports _________ so salt balance is upset
Causes a build up of _________________ in lungs and digestive organs .
protein
Cl- ions
thick mucous
Image from: BIOLOGY by Miller and Levine; Prentice Hall Publishing ©2006

15. Phenylketonuria (PKU)
CAUSE: Mutation in gene for an ___________ that __________ an ___________ called phenylalanine
Build up causes ________________________
ENZYME
breaks down
amino acid X X
MENTAL RETARDATION

16. Phenylketonuria (PKU)
ALL
tested
____ babies are ________
for PKU before they
leave the hospital.
Treatment: Need a diet _____________________ to extend life and ______________ mental retardation
If phenylalanine is an _____________,
what type of foods should PKU patients avoid? __________________
LOW in phenylalanine
PREVENT
amino acid
PROTEINS !

17. TAY-SACHS DISEASE ___________________
AUTOSOMAL RECESSIVE
CAUSE: Mutation in gene for an ___________ that breaks down a kind of _________in the developing _________
Build up of lipids in brain cells leads to: mental retardation, blindness, and DEATH in early childhood
ENZYME
LIPID
BRAIN
Found more frequently in people with _______ _____________ ______________, ancestry
Jewish
Mediterranean
Middle Eastern
Image from:

18. Tay-Sachs

19. CARRIER heterozygous A __________ person who carries a
_________ allele for a
genetic disorder, but
______________ the
disorder themselves
is called a
_____________
heterozygous
recessive
doesn’t show
CARRIER

20. A male who is a heterozygous carrier for an autosomal recessive disease marries a homozygous unaffected female. What is the chance of having an affected child? A child who is a carrier?
50 %; 50%
0%; 50%
50%; 0%
25%; 50%

21. DOMINANT AUTOSOMAL DOMINANT Huntington’s disease Achondroplasia
A mutation that codes for a new protein
whose action masks the normal allele
appears as a ______________ mutation.
Examples of _________________________ GENETIC DISORDERS:
____________________
DOMINANT
AUTOSOMAL DOMINANT
Huntington’s disease
Achondroplasia

22. HUNTINGTON’S DISEASE ______________________
AUTOSOMAL DOMINANT
CAUSE: Extra ______________ at end of gene on chromosome 4
The _____________ the more __________ the symptoms.
CAG repeats
more repeats
severe

23. HUNTINGTON’S DISEASE loss
Huntington’s brain
loss
Causes progressive _____ of ________________ and ___________function
muscle control
mental
1 in 10,000 people in U.S.
have Huntington’s disease
Normal brain

24. A person with
Huntington’s disease
has a _____ chance of
passing the disorder on to
their offspring.
50%
Problem: Symptoms of disorder usually don’t show until ____________ . . .
so you don’t know you have it until ________ you have had children.
MIDDLE AGE
AFTER

25. ACHONDROPLASIA (One kind of Dwarfism)
AUTOSOMAL DOMINANT
CAUSE: ___________________________ gene
1 in 20,000 births
Mother has achondroplasia
Father has diastrophic displasia, a recessive disorder
200,000 “little people” worldwide

26. Autosomal Dominant Disorders
Achondroplasia
99.96% of all the people in the world are homozygous recessive for this trait (aa).
Interesting fact: The AA (homozygous dominant) genotype of this trait is lethal and will result in a spontaneous abortion of the fetus.
The only viable genotype is Aa.

27. Activity 1: With a partner
Take 5 minutes and draw a two-circle Venn Diagram to compare and contrast:
Autosomal recessive Vs. autosomal dominant

28. BY ____________________
DISORDERS CAUSED
BY ____________________
____________________
AUTOSOMAL CODOMINANT ALLELES
SICKLE CELL DISEASE
CAUSE: T changed to A in gene for
__________________
(protein in red blood cells
that carries oxygen in blood)
HEMOGLOBIN

29. SICKLE CELL DISEASE SYMPTOMS:
_____________ become sickle shaped in persons with ______
sickle cell ________
RED BLOOD CELLS
TWO
ALLELES

30. SICKLE CELL DISEASE Circulatory problems Cells stick in capillaries
Loss of blood cells (anemia)
Organ damage (brain, heart, spleen)
Can lead to DEATH

31. SICKLE CELL DISEASE
AFRICAN AMERICANS
More common in _________________
1 in 500 = have sickle cell disease
1 in 10 = carriers for allele
Also affects persons of _______________ and _________________ descent
Why do so many African Americans carry the sickle cell allele?
MEDITERRANEAN
MIDDLE EASTERN

32. SICKLE CELL DISEASE Many can trace their ancestry to west
central Africa where ___________,
a serious parasitic disease that
infects red blood cells is common.
MALARIA
Images from:

33. HOMOZYGOUS sickle cell sickle disease HOMOZYGOUS malaria HETEROZYGOUS
A person who is __________________ for the ____________allele (ss) will have _______________
A person who is _________________ for normal hemoglobin alleles will have normal blood cells, but can become infected with __________ (SS)
A _________________ person (Ss)
(with one normal/one sickle cell allele) is
generally healthy and has the benefit of
being _________ to malaria
sickle cell
sickle disease
HOMOZYGOUS
malaria
HETEROZYGOUS
resistant

34. Chromosomes that determine the sex of an organism = _________________
All other chromosomes = _________________
Sex chromosomes
autosomes
Humans have two sex chromosomes
and _____ autosomes X y 44

35. SEX DETERMINATION
XX =
female
Xy =
male

36. Who decides? X X Mom can give X X Dad can give X or y y X X X X X y
SO ____ determines sex of the baby.
If dad gives X with mom’s X = girl
If dad give y with mom’s X = boy

37. Sex linked genes
In addition to their role in determining sex of an organism, X and Y chromosomes have many other genes that are unrelated to sex.
A gene on either sex chromosome is call a sex-linked gene.
Congenital generalized hypertrichosis (CGH), the type that Danny Gomez has, is X-linked dominant; the gene that is mutated is found on the X chromosome.
Sex-linked mutations can be either dominant or recessive.
X-linked inheritance pattern from a heterozygote mother and unaffected father

38. PEDIGREES
_______________are diagrams that show how are ____________ on __________ over several generations
genes are passed
in families

39. Drawing a pedigree chart

41. Genes carried on X or Y chromsomes= ___________________
SEX LINKED TRAITS
These traits show up in different
_______________ in males and females
because they move with the sex chromosomes
percentages

42. EXAMPLE: Hairy pinna Y linked in males Y-LINKED GENES:
Genes ______________ chromosome
carried on Y
EXAMPLE: Hairy pinna
ONLY
Y linked
in males
_________genes _____ show up _______

43. are carried on the X chromosome
X-LINKED
____________ GENES:
are carried on the X chromosome
X-linked recessive disorders
show up _____________
in ______ than females
because males only have
______ X chromosome.
MORE frequently
MALES
ONE

44. Or Males ONLY HAVE ONE X They either have the They are disorder normal
DEFECTIVE
NORMAL
They either
have the
disorder
They are
normal Or

45. Females have one normal gene that works.
FEMALES HAVE TWO X CHROMOSOMES
DEFECTIVE
NORMAL
DEFECTIVE
Females have one normal gene that works.
Females __________ defective recessive
alleles to show the
disorder
need 2

46. X-LINKED RECESSIVE
Examples of ________________________ DISORDERS:
____________________
HEMOPHILIA
COLORBLINDNESS
DUCHENNE MUSCULAR DYSTROPHY

47. HEMOPHILIA Blood clotting proteins on X bleed to death
CAUSE: Mutation in genes for __________________ carried ______ chromosome
Blood clotting proteins are missing so person with this disorder can’t stop bleeding when injured; can ________________ from minor cuts or suffer internal bleeding
from bruises or bumps.
Blood clotting proteins
on X
bleed to death

48. COLORBLINDNESS Color vision Red-green
CAUSE: Mutation in one of three genes for _______________ carried on X chromosome
Persons with this disorder have trouble distinguishing colors.
_________________
colorblindness is most common
Seen in 1 in 10 males
1 in 100 females
Color vision
Red-green

49. Duchenne Muscular Dystrophy
CAUSE:
deletion in gene
that codes for a
_______________
Results in
____________________
and loss of ___________________
muscle protein
progressive weakening
skeletal muscle

50. ________ traits show up _______ in _______ __________________ traits:
What’s the pattern:
________ traits show up _______ in _______
__________________ traits:
______________________ than females.
________________ can be ________.
_______________________ traits:
BOTH ______ & _________ can be ________
Y-linked ONLY males
X-linked recessive
more common in males
ONLY FEMALES carriers
AUTOSOMAL RECESSIVE
MALES FEMALES carriers

51. Activity 2 (group): Interpreting pedigrees
Using your pedigree reference sheet, try to identify the inheritance pattern for each pedigree on the handout.
Is it:
Sex-linked dominant?
Autosomal dominant?
Autosomal recessive?

52. ____________________________: Change in the ______________ or
CHROMOSOMAL MUTATIONS
____________________________:
Change in the ______________ or
____________ of chromosomes
structure
number

53. Homologous chromosomes ________________ during MEIOSIS
= _________________________
One cell gets 2 copies of
the chromosome the
other cell gets none.
fail to separate
NONDISJUNCTION

54. Normal Meiosis Nondisjunction

55. Human Abnormalities caused by Non-Disjunction __________________ __________________ __________________
Down syndrome
Klinefelter syndrome
Turner syndrome

56. Down syndrome (= ____________)
TRISOMY 21

57. Non-Disjunction Disorders
Down Syndrome (1:700)
Characterized by obvious physical features and mild to profound mental disabilities.
Short stature, heart defects, short lifespan, often sexually underdeveloped and sterile.
Caused by a duplication of the 21st chromosome (47 TOTAL) = TRISOMY 21.

58. Turner syndrome – “monosomy”

59. Non-Disjunction Disorders
Turner’s Syndrome (1:5,000)
THIS SYNDROME IS THE ONLY VIABLE MONOSOMY WHICH EXISTS IN HUMANS.
98% of these fetuses die prior to birth
Individuals affected with this disorder develop as females only.
Occurs when all or part of one of the X chromosomes is missing (45 TOTAL) =MONOSOMY X.
Characterized by short stature, webbed neck, stocky build and absence of sexual development; normal intelligence.

60. Klinefelter syndrome XXy

61. Non-Disjunction Disorders
Klinefelter’s Syndrome
A condition which occurs in males only.
Individuals with this disorder have an extra X sex chromosome (47 TOTAL) = TRISOMY XXY.
This disorder can affect the stages of language, physical, and social development.
Characteristics include small testes, breast enlargement and other feminine body attributes; normal intelligence.

62. Which disorder is this?

63. Which disorder is this?

64. Which disorder is this?

65. Polygenic traits – Eye color

66. Compare and contrast Complete dominance Incomplete dominance
Co-dominance
Sex-linked