The field that studies the links between Genetics and Biochemistry, for instance by finding which Genes that control certain Metabolic pathways, and how they do it.

One major focus area involves diagnosing and treating metabolic hereditary diseases.

Garrod and inborn errors of metabolism – Garrod, Beadle, Tatum and the link between genetics and biochemistry

Yeast as a model organism

Mutant hunting

How to use genetics to study biochemistry: A mutant hunt

Tricks of mutant hunting

• Replica plating
• Use haploids, if you can, like in yeast. Benefits depend on whether mutation is dominant or not.
• Test of dominance. Mate a heterozygote with a homozygote
• Tests of Complementation – explanation, only works for recessive. Table to organize complementation tests. Nice example
  • If the mutations complement each other –> different genes
  • If they fail to complement each other –> same gene
  • These define complementation groups
• Epistasis test. Sometimes phenotypes of double mutants are the same as hose of single mutants, when the extra mutation affects something upstream in a Metabolic pathway that the other mutation affects. Can use this to find order of steps in the pathway.

Gene knock-outs are useful in these studies!