14.1 What Is the Evidence that Genes Code for Proteins?
14.2 How Does Information Flow from Genes to Proteins?
14.3 How Is the Information Content in DNA Transcribed to Produce RNA?
14.4 How Is Eukaryotic DNA Transcribed and RNA Processed?
14.5 How Is RNA Translated into Proteins?
14.6 What Happens to Polypeptides after Translation?
The molecular basis of phenotypes was discovered before it was known that DNA is the genetic material.
Studies of many different organisms showed that major phenotypic differences were due to differences in specific proteins.
Identification of a gene product as a protein began with a mutation.
Garrod saw a disease phenotype— alkaptonuria—occurring in children who shared more alleles as first cousins.
A substance in their blood (HA, homogentistic acid) accumulated—was not catalyzed—the gene for the enzyme was mutated.
Garrod correlated one gene to one enzyme.
Model organisms: Easy to grow or observe; show the phenomenon to be studied.
Can assume that results from one organism can be applied to others.
Examples: Pea plants; Drosophila; C.elegangs, E. coli; common bread mold, Neurospora crassa.