The Biology of DNA

1
The Biology of DNA
February 14, 2008
Jack T. Leonard, Ph.D.
2
Outline

• DNA Structure and Function
• Central Dogma- DNA/RNA/Protein
• The Universal Genetic Code
• Genomics and Genetics
• DNA Ancestry
• DNA in Health and Medicine

3
DNA Structure
Base pairs
Bases A Adenine T Thymine G Guanine C Cytosine
Okay, but how do you get the information to make
proteins from only 4 DNA bases?
4
The Universal Genetic Code is used by all forms
of life
Bacteria, plants, animals, fungi and viruses
3 letter code for translation from RNA to proteins
Codons in mRNA
Amino acids are the building blocks for proteins
5
A Simpler View of Codons
Genes
Codons
Protein
6
DNA is the code (genes)
RNA is the message
Proteins are the catalysts enzymes
7
Central Dogma in a Eukaryotic Cell
Both Replication of DNA and Transcription of DNA
to mRNA takes place in the nucleus.
mRNA is transported out of the nucleus through
nuclear pores and into the cytoplasm.
Translation of mRNA into proteins is the task of
1,000s of ribosomes in the cytoplasm and
endoplasmic reticulum.
Proteins encoded in your DNA help you digest your
lunch, to think, and to ride your bike among
other things.
8
The Human Genome Project 3.2 Billion basepairs
on 23 chromosomes. Determined every position on
human DNA by sequencing. Two of each chromosome
(diploid) approximately 25,000 different genes
Sex chromosomes
XX female XY male
.AGCCGTTATCGTTACGAAAACTAGTAAAGCGCATAT.
9
Deep DNA Ancestry Research for 99!
www.genographic.com
10
How do they trace ancient human migrations?
Surname Paternal line Y chromosome
Maternal line Mitochondrial DNA
11
Genetic Diseases
25 Chance of Genetic Disorder with Two Carriers

• Cystic Fibrosis
• Sickle Cell Anemia
• Alpha-1 Antitrypsin Deficiency
• Alpha- and Beta-Thalassemia,
• Phenylketonuria
• Tay Sachs
• Gaucher
• Hemochromatosis

HH
Hh
Hh
hh
12
MALARIA- a deadly infectious disease
Annually, there are 500 million cases of malaria,
and more than 1 million malaria-associated deaths.

• Malaria is carried by mosquitoes in tropical and
  subtropical regions of the world including
  sub-Saharan Africa, Brazil, Thailand, Vietnam,
  Cambodia, China, Sri Lanka, Indonesia and
  Afghanistan.

• Malaria is spread by the bite of an infected
  mosquito which transmits a protozoan parasite.

Plasmodium growing in a mosquito hindgut.
Mosquito infecting a human while feeding.
13
Sick with or Vulnerable to Malaria
HH- 3 in 4
Normal Hemoglobin
Genetic Disease
Healthy
Hh- 1 in 4
hh- 1 in 50
Sickle Cell Anemia
Sickle Cell Trait
14
Careers in DNA

• Biotechnology- Develop new medicines.
• Geneticist- Provide medical advice.
• Molecular biologist- General DNA Research.
• Product Development- Invent new research tools
  for scientists.
• Professor- Teaching and/or research.
• Genomics- Sequence DNA.
• Bioinformaticist- Computer Programming and
  understanding DNA sequence data.

15
Additional Information Cool YouTube Videos

• DNA Replication http//www.youtube.com/watch?v5U
  oKYGKxxMIfeaturerelated
• The Inner Life of Cells http//www.youtube.com/wa
  tch?vkxSLw1LMvgk
• The Human Genome Project http//www.youtube.com/w
  atch?vx0mFEq6aOCMfeaturerelated