1. DNA Interlude

2. Classwork
Introduce yourself to your neighbor Everyone get into groups of 3 Carefully retrieve one piece of chart paper In groups, summarize DNA replication as a series of steps

3. DNA
What is it?

4. DNA
Most commonly thought of as a
“Double-stranded helix”

5. Human DNA
Genome: complete set of genetic information in an organism

6. Human DNA A full set of human DNA (1n) is about 3 billion bp long
Normal somatic cells are 2n so have roughly 6,000,000,000 bp

7. Human DNA Human chromosomes vary in length from:
Chromosome 1 is about 250 million bp
Chromosome 21 is about 48 million bp

8. Human DNA
Current estimates put the number of genes in the human genome at about 20,000
This means that less than 1.5% of the human genome is taken up by protein-coding genes
Over 98% is other “stuff”

9. Human genome
First human genome was completely sequenced by the year 2003
Currently, we are in the realm of having sequenced thousands of human genomes
Sequence of the genome is available at