One1 - of metabolism". He also discovered...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
One-gene-one-protein During the 1930s, despite great advances, geneticists had several frustrating questions yet to answer: What exactly are genes? How do they work? What produces the unique phenotype associated with a specific allele? Answers from physics, chemistry, and the study of infectious disease gave rise to the field of molecular biology. Biochemical reactions are controlled by enzymes , and often are organized into chains of reactions known as metabolic pathways . Loss of activity in a single enzyme can inactivate an entire pathway. Archibald Garrod, in 1902, first proposed the relationship through his study of alkaptonuria and its association with large quantities "alkapton". He reasoned unaffected individuals metabolized "alkapton" (now called homogentistic acid) to other products so it would not buildup in the urine. Garrod suspected a blockage of the pathway to break this chemical down, and proposed that condition as "an inborn error
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: of metabolism". He also discovered alkaptonuria was inherited as a recessive Mendelian trait. George Beadle and Edward Tatum during the late 1930s and early 1940s established the connection Garrod suspected between genes and metabolism. They used X rays to cause mutations in strains of the mold Neurospora . These mutations affected a single genes and single enzymes in specific metabolic pathways. Beadle and Tatum proposed the "one gene one enzyme hypothesis" for which they won the Nobel Prize in 1958. Since the chemical reactions occurring in the body are mediated by enzymes, and since enzymes are proteins and thus heritable traits, there must be a relationship between the gene and proteins. George Beadle, during the 1940s, proposed that mutant eye colors in Drosophila was caused by a change in one protein in a biosynthetic pathway....
View Full Document

Ask a homework question - tutors are online