1. Chapter 12 Inheritance Patterns and Human Genetics

2. 12.1 Objectives Distinguish between sex chromosomes and autosomes.
Explain the role of sex chromosomes.
Know the difference between chromosome mutations and gene mutations.

3. I. Chromosomes What is a Chromosome? Sex Chromosomes
A vehicle of genetic information
Sex Chromosomes
Determine the sex of organisms
XX = female
XY = male
Information on these chromosomes gives the organism the sex specific characteristics.

4. C. Autosomes
1. the remaining chromosomes
2. 22 pairs

5. II. Chromosome Mutations
Chromosome Deletion
Loss of a piece of chromosome
Chromosome inversion
Chromosome breaks off; flips and reattaches
Chromosome translocation
One chromosome breaks and reattaches to another
Nondisjunction
Chromosomes fail to separate correctly resulting in an extra copy.

6. III. Diseases from Chromosome Mutations
Down Syndrome (Trisomy 21)
Extra copy of chromosome #21
Distinct facial features
Heart defects
Shorter lifespan
Early Alzheimers
Some degree of mental retardation

8. B. Turner’s Syndrome Only have 1 X chromosome; no other X or Y
Genetically female
Do not mature sexually; are sterile
Short stature
Normal intelligence

11. C. Klinefelter Syndrome
A. males have an extra X chromosome (XXY)
B. male sex organs
C. may have feminine characteristics
D. normal intelligence

13. D. Patau Syndrome (Trisomy 13)
serious eye, brain, and circulatory defects
Clef palate
Children only live a few months

15. Cleft Palate

16. Cleft Palate

18. E. Edward’s Syndrome Trisomy 18 Most children only live a few months
All major organs affected

21. Sex Linked Inheritance
Gene for disease is found on X chromosome.
Usually recessive.
Affects less females.
Females may have the recessive gene but it can be covered up by the normal dominant gene on the 2nd X chromosome
Affects more males
Since males only have 1 X chromosome, the recessive gene will be expressed if present.

22. Red/Green Colorblindness
The gene which allows us to distinguish between red and green is on the X chromosome. X C
= Female with normal vision X C c
= Female carrier X c
= Female who is colorblind

23. Red/Green Colorblindness
The gene which allows us to distinguish between red and green is on the X chromosome. X C Y
= Male with normal vision X c Y
= Male who is colorblind

24. Pedigree XY XX XY XY XX Marriage Mother Father Children Daughter Son
Oldest
Youngest

25. A family history of a genetic condition
PEDIGREE CHARTS
A family history of a genetic condition
© 2007 Paul Billiet ODWS

26. What is a pedigree chart?
Pedigree charts show a record of the family of an individual
They can be used to study the transmission of a hereditary condition
They are particularly useful when there are large families and a good family record over several generations.
© 2007 Paul Billiet ODWS

27. Symbols used in pedigree charts
A marriage with five children, two daughters and three sons. The 2nd eldest son is affected by the condition.
Eldest child  Youngest child
Normal male
Affected male
Normal female
Affected female
Marriage
© 2007 Paul Billiet ODWS

28. Organising the pedigree chart
Generations are identified by Roman numerals I II
III IV
© 2007 Paul Billiet ODWS

29. Some History
Hemophilia has played an important role in Europe's history
The disease began to crop up in Great Britain's Queen Victoria’s children
It became known as the "Royal disease" because it spread to the royal families of Europe through Victoria's descendants

30. How it Spread
it spread through the Royal Houses of Europe as monarchs arranged marriages to consolidate political alliances.
We can trace the appearance of hemophilia as it popped up in Spain, Russia, and Prussia by looking at the family tree.

31. The Royal Family Tree

32. Pedigree Karyotype

33. Genetic Disorders

34. Huntington’s Disease Gradual brain deterioration Middle age
Dominant trait found on chromosome 4
1 in 10,000
Movie: Love and Other Drugs

36. Cystic Fibrosis Mucus clogs lungs and pancreas
Use to cause early death now victims can live to early adulthood
Recessive gene on chromosome 7
1 in 900 French Canadiens
1 in 2000 Europeans

38. Sickle Cell Anemia Organ damage due to impaired blood flow
Recessive gene on chromosome 11
1 in 500 African Americans

40. Tay Sachs Disease Deterioration of nervous system
Waste build up causes nerve cell death
Autosomal recessive gene on chromosome 15
1 in 600 Jews of European decent

42. Marfan Syndrome Long limbs Loose joints Deformed spine Crowded teeth
Dominant gene on chromosome 15
1 in Americans
Abe Lincoln

44. Breast Cancer (BRCA -1) Malignant tumors in breast tissue
Dominant gene on chromosome 17
8% of breast cancer