1. 7.1 Chromosomes and Phenotype: Autosomal Genetic Disorders
Set up Cornell Notes on pg. 81
Topic: 7.1 Chromosomes and Phenotype: Autosomal Genetic Disorders
Essential Questions:
Why is it impossible to have a “carrier” of an autosomal dominant disorder?
7.1 Chromosomes and Phenotype: Autosomal Genetic Disorders
2.1 Atoms, Ions, and Molecules
Why is it impossible to have a “carrier” of an autosomal dominant disorder?
KEY CONCEPT The chromosomes on which genes are located can affect the expression of traits.

2. P Video Notes
Autosomal Recessive Disorder
Albinism
Treacher-Collins Syndrome

3. KEY CONCEPT The chromosomes on which genes are located can affect the expression of traits.

4. Many human genetic disorders are caused by autosomal genes, and can be predicted the same as flower color, or Pea shape
Autosomal genetic disorders: disorders that have no relation to the sex of an individual
Can be male or female in equal proportions
Ex: Albinism

5. Any offspring with two recessive genes (cc) will have the disease/disorder
Ex: Cystic Fibrosis C c Cc cc

6. A carrier is heterozygous (Cc) for a recessive disorder and does not show any signs or symptoms, but can pass on the disorder to their offspring
Please label each box with: Carrier/Disorder/Normal
C c CC Cc
Ex: Cystic Fibrosis C
Normal
*carrier c Cc cc
*carrier
Disorder

7. Video: Autosomal Recessive Disorders (4m52s)
Pg Take at least 10 bullets

8. Albinism is a autosomal recessive disorder characterized by a lack of pigment in skin, hair, and eyes (race/gender does not matter!!!!)
Can affect ANY animal in the animal kingdom

12. A a A a A a Genotype: Genotype: Phenotype: Phenotype: Carriers?:
mom
mom
A a
A a
dad
dad A a
Genotype:
Phenotype:
Carriers?:
Albinism?:
Are either of the parents albino?
Genotype:
Phenotype:
Carriers?:
Albinism?:
Are either of the parents albino?
Please label: normal/carrier/disorder

13. A a A a A a AA Aa *carrier Aa *carrier aa *disorder AA Aa *carrier Aa
Genotype: AA, Aa
Phenotype:
O% albino
100% non-albino
Carrier?: 50% carrier
Albinism?: 0% albino
Parents?: Neither parent is albino
Genotype: Aa, aa
Phenotype:
50% albino
50% non-albino
Carrier?: 50% carrier
Albinism?: 50% albino
Parents?: Father is albino

14. Both Mom and Dad have to either have the disorder or be carriers for offspring to be affected with an autosomal recessive disorder!

15. Video: ABC’s Special Report: Albinism- Caught between light and dark (6m54s)
5-7 bullets
NON TRADITIONAL NOTES
Social issues?
Physical/Health issues?
Any other notations you make

16. Autosomal DOMINANT Disorders: any offspring with a dominant allele will have the disorder
Dominant disorders are uncommon
No carriers! ( Hh- would show the trait)
H h H
*anywhere there is an H the child will have the disease h

17. Huntington’s disease is a autosomal dominant disorder in which nerve cells in certain parts of the brain waste away, or degenerate. The disease is passed down through families.
Causes
Huntington disease is caused by a genetic defect on chromosome 4. The defect causes a part of DNA, called a CAG repeat, to occur many more times than it is supposed to. Normally, this section of DNA is repeated 10 to 28 times. But in persons with Huntington disease, it is repeated 36 to 120 times.
As the gene is passed down through families, the number of repeats tend to get larger. The larger the number of repeats, the higher your chance of developing symptoms at an earlier age. Therefore, as the disease is passed along in families, symptoms develop at younger and younger ages.
Normal brain
HD brain

18. H h H h Huntington’s Disease Genotype: Phenotype:
*anywhere there is an H the child will have the disease

19. HH Hh Hh hh H h H h Huntington’s Disease Genotype: HH, Hh, hh
Phenotype:
75% Huntington’s Disease
25% non-H’s D H HH Hh
Disorder
Disorder Hh h hh
Disorder
*anywhere there is an H the child will have the disease

20. Treacher Collins Syndrome is an autosomal Dominant disorder.
It can lead to the person having no cheekbones or very small cheekbones (so the eyes droop), and they may also have a cleft palate, under developed ears, and an very small jaw.

21. T t t Tt *disorder tt Tt *disorder tt Genotype: Phenotype:
If Mom or Dad have the disorder 50/50 chance the offspring will also have the disorder.
Genotype: Tt, tt
Phenotype:
50% will have TCS
50% non-TCS

22. Video: Ashley’s Story- Treacher Collins Syndrome (5m11s)
5-7 bullets
NON TRADITIONAL NOTES
Social issues?
Physical/Health issues?
Any other notations you make

23. How did Ashley inherit the disease if neither of his parents had it?
This condition is caused by a change in a single gene. The Treacher Collins syndrome gene is on chromosome 5. Over 50 different changes in the gene are known to cause Treacher Collins syndrome.
In about 60% of people with Treacher Collins syndrome the change in their gene happened for the first time in them. This means that there is little chance of this person’s parents or brothers or sisters having any children with Treacher Collins syndrome. In about 40% of people with Treacher Collins syndrome one of their parents also has the same gene chance.

24. 7.1 Chromosomes and Phenotype: Sex-linked Genes
Set up Cornell Notes on pg. 83
Topic: 7.1 Chromosomes and Phenotype: Sex-linked Genes
Essential Questions:
1. Describe how Sex-linked genes are expressed differently in men than women.
7.1 Chromosomes and Phenotype: Sex-linked Genes
2.1 Atoms, Ions, and Molecules
1. Describe how Sex-linked genes are expressed differently in men than women.

25. Punnett Square work 82

26. Gene expression is often related to whether a gene is located on an autosome or a sex chromosome
Sex chromosomes: determine gender
Y chromosome genes in mammals are responsible for male characteristics.
X chromosome genes in mammals affect many traits.
Autosomes: all other chromosomes- no relation to gender
All genes that Mendel studied were autosomes
Most traits are the result of autosomal genes
REVIEW

27. 25% will have white eyes as expected (similar to autosomal findings)
Because the X and Y chromosomes have different genes, sex-linked genes have a pattern of expression that is different from autosomal genes
25% will have white eyes as expected (similar to autosomal findings)
BUT ALL will be male!
Crossing 2 heterozygous

28. X X X X X X Female mammals have an XX genotype.
Expression of sex-linked genes is similar to autosomal genes in females.
X X A A
X X A a
*carrier
X X a a
*disorder

29. Males have no second copies of sex-linked genes, so ALL of a male’s sex-linked genes are expressed
Even if all the sex-linked genes of a male are recessive, they will be expressed
There is no second “X” to mask the recessive gene
X Y A
X Y a
*disorder

30. Genes on sex chromosomes are called sex-linked genes.
% chance of male offspring showing recessive trait?
% chance of female offspring showing recessive trait? A A A A A X X X X X A A Y X Y Y X

31. Genes on sex chromosomes are called sex-linked genes.
% chance of male offspring showing recessive trait? 0%
% chance of female offspring showing recessive trait? A A A A A X X X X X A A Y X Y Y X

32. Genes on sex chromosomes are called sex-linked genes.
% chance of male offspring showing recessive trait?
% chance of female offspring showing recessive trait? A A A A a X X X X X A a Y X Y Y X

33. Genes on sex chromosomes are called sex-linked genes.
% chance of male offspring showing recessive trait?
50%
% chance of female offspring showing recessive trait? 0% A A A A a X X X X X A a Y X Y Y X

34. Examples of sex linked disorders
Color-blindness
Hemophilia
Muscular Dystrophy

35. Color blindness is a recessive sex-linked trait.
A non-colorblind man marries a woman who is a carrier for color blindness. Predict the heredity of their offspring. (Use “b” to show color blindness)
Phenotypes:
Male-
______% colorblind
______% Non-colorblind
______% Carrier
Female-

36. Color blindness is a recessive sex-linked trait.
A non-colorblind man marries a woman who is a carrier for color blindness. Predict the heredity of their offspring. (Use “b” to show color blindness)
Phenotypes:
Male-
50% Colorblind
50% Non-CB
NO CARRIERS
Female-
0% Colorblind
100% Non-CB
50% carrier X B X b b B B B B X X X X X B X Y b Y X Y

37. Sex Linked Inheritance (5m15s)

38. A white-eyed male fly mates with a red eyed female fly to produce: 24 white-eyed males, 27 white-eyed females, 26 red-eyed males, and 23 red-eyed females. Can this trait be sex-linked? Prove your answer by completing 2 Punnett squares. (r=white eyes)
Phenotypes:
Male-
____% Red eyes
____%White eyes
Female-

39. A white-eyed male fly mates with a red eyed female fly to produce: 24 white-eyed males, 27 white-eyed females, 26 red-eyed males, and 23 red-eyed females. Can this trait be sex-linked? Prove your answer by completing 2 Punnett squares. (r=white eyes)
White eyes is a recessive sex-linked trait. X R X R
Phenotypes:
Male-
100% Red eyes
0% White eyes
Female-
100% Red Eyes R r R r r X X X X X R X Y R Y X Y

40. X X X X X X X X Y Y X Y White eyes is a recessive sex-linked trait.
A white-eyed male mates with a red eyed female to produce: 24 white-eyed males, 27 white-eyed females, 26 red-eyed males, and 23 red-eyed females. Can this trait be sex-linked? Prove your answer by completing 2 Punnett squares. (r=white eyes) X R X r
Phenotypes:
Male-
50% Red eyes
50% White eyes
Female-
50% Red Eyes R r r r r X X X X X R X Y r Y X Y

41. Sex Linked Genes (8m9s-10m17s)

42. Sex Linked inheritance Penny Lab
Background
The relationship between genotype and phenotype in sex-linked genes differs from that in autosomal genes. A female must have two recessive alleles of a sex-linked gene to express a recessive sex-linked trait. Just one recessive allele is needed for the same trait to be expressed in a male.
Purpose
To model the inheritance pattern of sex-linked genes based on probability
Materials
Coins (2) – prelabeled
Genetic cross (given by teacher)

43. Sex Linked inheritance Penny Lab
Procedure
1) One coin represents the egg cell and the other coin represents the sperm cell. In the Data/Results section of your lab, record the genetic cross you were given.
2) Fill in the Punnett square for the given genetic cross.
3) Determine the expected genotypic and phenotypic ratios.
Use the key: A = does not have trait a = has the trait
4) Flip the two coins and record the genotype of the “offspring” in the count (tally marks) row of the data table under the appropriate given possible genotype.
5) Repeat step 4 until you have modeled 100 genetic crosses.
6) Calculate the total number of each genotype and the % of each type in your data table.

44. X chromosome inactivation randomly “turns off” one X chromosome
Ensures that females, like males, have one functional copy of the X chromosome in each body cell
Like a flip of a coin to determine which “X” turns off
P. 83

45. X Inactivation (6m22s)

46. X Chromosome inactivation example:
Tortoiseshell and Calico Cats (tend to always be female)
The female cats have white fur; and black (b) or orange fur (B) alleles on their X Chromosomes- these will be expressed randomly
Males have white fur; and one sex-linked gene for either black (b) or orange (B) fur X

47. Males only have one X chromosome so one color will be present
Female cats have two X chromosomes.
Each patch of fur can be different depending on which X chromosome “turns off” R B
B B
R R
X Y
X Y
X X
X X
B R
X X B R B R

48. X B X B B R
X X
X-chromosome inactivation X R
Black Y

49. X B X B B R
X X
X-chromosome inactivation X R
Orange Y

50. X B X B B R B R
X X
X X X R
Calico
Calico B
X Y B
X Y Y
Black
Black

51. X B X R X B Y
Answer the following questions:

52. What are the chances of getting a black cat?
Answer the questions about your cat cross:
What are the chances of getting a black cat?
What are the chances of getting an orange, male cat?
What are the chances of a male cat being black?
What are the chances of a female being calico?

53. X B X R B B B R
X X
X X X B
Black
Calico B
X Y R
X Y Y
Black
Orange

54. What are the chances of getting a black cat? 50%
Answer the questions about your cat cross:
What are the chances of getting a black cat?
50%
What are the chances of getting an orange, male cat?
What are the chances of a male cat being black?
What are the chances of a female being calico?

55. Sex Linked Inheritance Worksheet