Lab Exam

1
Lab Exam
2
Linkage Mapping
3
Chromosomal Basis of Inheritance
4
Independent Assortment
5
2-Locus Test Cross
Expected assumes Independent Assortment
6
Deviation from Expected
7
Linkage
8
Frequency of Recombination
9
Constructing Genetic Maps
10
Gender Sex Linkage
11
Gender Determination
12
Sex-Linkage (in mammals)
13
Sex-Linkage Inheritance Patterns
Dominant or Recessive Sex-Linked Inheritance?
14
Hemophilia in the Russian Royal Family
15
Dosage Compensation Nondisjunction
16
Barr Bodies Dosage Compensation
17
Nondisjuction
18
Common Aneuploidies

• Polyploidies (e.g., in plants) are actually less
  serious than one too many (or one too few)
  autosomes
• Most abnormalities in numbers of autosomes
  (anueploidies) are very serious or fatal due to
  gene dosage imbalances
• The fewer genes unbalanced, the less serious the
  condition
• Downs syndrome Caused by a trisomy of
  chromosome number 21 (1 in 700 births)mental
  retardation, mongoloid features, and heart
  defects
• Most abnormalities of sex chromosomes do not
  affect survival
• Klinefelter Syndrome Males with an extra X
  chromosome (XXY) (1 in 1000 male births)
• Turner Syndrome Females missing one X chromosome
  (XO) (1 in 2500 female births)

19
Down Syndrome
20
XO Turner Syndrome
Turner Syndrome (XO), Incidence 1 in 2500 female
births
21
XXY Klinefelter Syndrome
Klinefelter Syndrome (XXY), Incidence 11000
male births
22
Super Male
23
Additional Complications
24
Chromosomal Rearrangements
25
Genomic Imprinting
26
Cytoplasmic Inheritance
27
Link to Next Presentation
28
Acknowledgements
http//207.233.44.253/wms/reynolmj/lifesciences/le
cturenote/bio3/Chap09.ppt http//www.ucl.ac.uk/uc
bhjow/medicine/RGD_lectures/modes_of_inheritance.p
pt http//www.bbchs.k12.il.us/Teacher_Pages/Hammon
d/Powerpoint/Chapter_14.ppt
29
Sex-Linkage (in Drosophila)
30
Down Syndrome