Archibald Garrod - noted prevalence of diseases in certain families
- alkaptonuria - lack of enzyme leads to formation of alkapton (homogentisic acid) in urine
- believed that inherited diseases may be due to enzyme deficiencies
Beadle/Tatum - found that genes specify enzymes
- deliberately created mutations in chromosomes
- used X-rays to damage DNA in some yeast spores
- placed yeast in minimum medium (only contained sugar, ammonia, salts, water, vitamins)
- those that couldn’t make growth compounds would die
- material added to minimum medium to see what the yeast cells w/ damaged DNA lacked
- found that every enzyme had a different chromosomal site
- one-gene/one-enzyme hypothesis - genes produce effects by encoding for enzymes (aka one-gene/one-polypeptide hypothesis)
Frederick Sanger - found complete amino acid sequence for insulin
- 1st sequence to be determined for a protein
- showed that all proteins were just strings of amino acids in a certain order
Vernon Ingram - found molecular basis for sickle cell anemia
- found that change from glutamic acid to valine in the protein caused sickle cell anemia
- gene - sequence of nucleotides that determines the amino acid sequence of a protein
- some genes used to make special RNA forms