1. The Molecular Basis of Genetics Chapter 10: DNA Structure and Analysis
2. Replication
The flow of information:
1. Storage
3. Expression

2. DNA as the Genetic Material
Historically:
*1868 Friedrick Miescher
*1910 Phoebus Levene
tetranucleotide hypothesis
*1927 Frederick Griffith
transforming principle
*1944 Avery, MacLeod and McCarty
*1952 Alfred Hershey and Martha Chase

3. Evidence for DNA in Eukaryotes:
Indirect evidence:
*Distribution of DNA
*Mutagenesis
Organism n 2n
Human
3.25
7.30
Chicken
1.26
2.49
Trout
2.67
5.79
*RNA – genetic material in some viruses

4. Nucleotide Structure: Pentose sugar

5. Nucleotide Structure: Nitrogenous Bases

6. Structural Analysis of DNA:
*nucleoside
*nucleotide

7. Nucleic Acid Polarity *Top of molecule has free 5’-phosphate group
This is the 5’ end
*Bottom has a free 3’
hydroxyl group
This is the 3’ end

8. Base Composition: *1949-1953 Chargaff’s Rules Organism %G+C Phage T2
Source A T G C
A/T
G/C
A+G/C+T
A+T/C+G
Human
30.9
29.4
19.9
19.8
1.05
1.00
1.04
1.52
Sea Urchin
32.8
32.1
17.7
17.3
1.02
1.58
E. coli
24.7
23.6
26.0
25.7
1.01
1.03
0.93 T7
24.0
1.08
Organism
%G+C
Phage T2
36.0
Drosophila
45.0
Maize
49.1
Euglena
53.5
Neurospora
53.7

9. Complementarity

10. DNA Structure: *1953 Watson and Crick *Early 1950’s Rosalind Franklin
*Linus Pauling

11. RNA Structure: *Similar to DNA except: *Three major classes of RNA
S.R. Eddy (2001) Noncoding RNA genes and the modern RNA world, Nature Reviews Genetics, 2: