DNA Interlude

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

DNA What is it?

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

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

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

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

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”

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 http://www.ncbi.nlm.nih.gov/genbank/