Genomic Complexity

How many genes in the chromosome?• DNA or RNA?• Double Stranded or Single Stranded?• Shape?• Number of copies?• Size in base pairs?• Assume 400 amino acids per protein, then how many bases

per gene for a typical protein?• How many genes possible?• Do genes overlap?• Are both strands transcribed?

Consider the Ribosome

And its operon

Studying Macromolecules –Extracting DNA

Cell Pellet

Random fragments ~20-40 kbp

Extraction of Chromosomal DNA

• DNeasy Tissue Kit• Chromosomal

DNA, ~ 20-40 kbp size fragments

• Kim Foster

Chromosomal DNA

Chromosomal DNA

RNA

RNA

23 kbp

Hybridization

Quantitative Hybridization

Liquid Scintillation Counters

Photomultiplier Tubes

log Scale

Electronic Noise

3H 14C 32P

Spike

Experiment 1 – Total 14C-Uracil

10 µg DNA

10 µg RNA

5 µg RNA washes off

5 µg RNA sticks

Experiment 2 – rRNA 14C-Uracil

10 µg DNA

10 µg rRNA

>99% rRNA washes off

35 ng rRNA sticks

Experiment 3 – tRNA 14C-Uracil

10 µg DNA

10 µg tRNA

>99% tRNA does not stick

5 ng tRNA sticks