The Hereditary Material

1
The Hereditary Material

• Chromosomes consist of both DNA and Protein
• DNA was discovered before its role in heredity
  was understood
• People had a sense that chromosomes embodied
  inheritance before they understood that DNA was
  the hereditary material
• People did not want to believe that DNA was the
  hereditary material since it is not complex
  enough
• Instead, people believed that proteins must be
  the hereditary materialthey were wrong
• Transformation (I.e., Griffiths experiment,
  which is mediated by DNA) was discovered before
  it was understood that it was mediated by DNA

2
Griffiths Experiment (1928)
3
Avery, MacLeod, McCarty (1944)
Hi, Im Oswald Avery. I figured out that the
transforming principle is DNA!
Discovery that DNA was the Transforming Principle
4
Avery, MacLeod, McCarty (1944)
Hi, Im Colin M. MacLeod
Hi, Im Theodosius Dobzhanky. I wrote Genetics
and the Origin of Species (1937)
Hi, Im Maclyn McCarty
Colin M. MacLeod, Maclyn McCarty, Detlev Wulf
Bronk, Theodosius Dobzhansky, and Wendell M.
Stanley
Hi, Im Detley Wulf Bronk. I asked, Are aliens
living among us ???
Hi, Im Wendell M. Stanley. I crystalized (and
then X-rayed) tobacco mosaic virus!
5
Chargaffs Rule (1950)
6
Hersheys Experiment (1952)
7
Rosalind Franklin (1952/3???)
Who was working for/with (against?) Maurice
Wilkins
8
Watson Crick (1953)
9
Structure of DNA
10
Structure of Double Helix
11
Nucleotide Sequence
5 end 1 TTGGCGCaCC TATATATCTT TTCGCCCTCT
GAtATTCTGT TGGGTGTTCT 51 AGATCGCTTG
TTCAAAGATA ACGCTACCGG GAAGGTTCTT GCTTCCCGGG
101 TAGCTGTCGT AATTCTTTTG TTTATAATGG
CGATTGTTTG GTATAGGGGA 151 GATAGTTTNT
TTGAGTACTA TAAGCAATCA AAGTATGAAA CATACAGTGA
201 AATTATTGAA AAGGAAAGAA CTGCACGCTT
TGAATCTGTC ATCCTGGAAC 251 AACTCCAGAT
AGTTCATATA TCATCTGAGG CAGACTTTAG TGCGGTGTAT
301 TCTTTCCGCC CTAAAAACTT AAACTATTTT
GTTGATATTA TAGCATACGA 351 AGGAAAATTA
CCTTCAACGA TAAGTGAAAA ATCACTTGGA GGATATCCTG
401 TTGATAAAAC TATGGATGAA TATGCAGTTC
ATTTAAATGG ACGTCATTAT 451 TATTCCAGCT
CAAAATTTGC TTTTTTGCCA ACTAAAAAGC CTACTCCCGA
501 AATAAACTAC ATGTACAGTT GTCCATATTT
TAATTNGGAT AATATCTATG 551 CTGGAACAAT
AACCATGTAC TGGTATAGAA ATGATCATAT AAGTAATGAC
601 CGCCTTGAAT CAATATGTTC TCAGGCGGCC
AGAATATTAG GANGGGCTAA 651 ATAATTATTT
GTTTGTATAC ATCTCTAGAT ATCGATATAC ACCCNTCAAA
3 end
This is the sequence of gene t from bacteriophage
T2
12
DNA Replication Hypotheses
13
Meselson-Stahl Experiment (1957)
14
Semiconservative DNA Replication
15
DNA Replication Enzymes
16
Origin(s) of Replication
17
Nucleotide Addition
18
Nucleotide Addition
19
Priming Nucleotide Addition
DNA Polymerase Requirement for 3 OH
20
Leading vs. Lagging Strands
21
Ligation
22
DNA Replication Enzymes
23
The Replication Fork
24
More Replication Forks
25
Proofreading
26
The Problem of Ends
27
A Solution Telomeres
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Central Dogma Preview
29
Link to Next Presentation
30
Acknowledgements
http//207.233.44.253/wms/reynolmj/lifesciences/le
cturenote/bio3/Chap10.ppt http//www.bbchs.k12.il.
us/Teacher_Pages/Hammond/Powerpoint/Chapter_16.ppt