Erwin chargaff

Erwin Chargaff was born on August 11, 1905 in Chernivtsi, Ukraine. He studied at the University of Vienna and earned his doctorate in Chemistry. He went on to research at Yale and took a job as a professor at Colombia. He died on June 20, 2002 in New York City at the age of 96.

Chargaff's

CHARGAFF'S RULES

Rule

Base pair

(A-T interactions)

=

G

=

C

Purines = Pyrimidines

NA

G

Erwin Chargaff

Base pair

(G-C interactions)

@ Study.comi

What did he discover?

Chargaff discovered that in a strand of DNA the amount of adenine (A) is always equal to the amount of thymine (T), and cytosine (C) and guanine

(G) are always equal. This is now known as Chargaff's Rule.

He figured out that the proportion between the bases varies from specie to specie, but the ratio between A:T and C:G is always 1:1.

• How?

• Paper Chromatography

Chargait started by observing four nitrogenous bases found in different DNA samples, then he used paper chromatography to separate the substances and UV spectrophotometry to to count the amount of each base for each sample.

• When and Where?

This discovery happened at Colombia University, New York during the 1950s.

Paper Chromatorygraphy is a process that separates substances by using capillary actions to move solvent through paper. Chargaff used this because the separation allowed him to view the individual bases in each DNA sample.

• UV Spectrophotometry

UV spectrophotometry is a method used to measure the amount of ultra-violet and visible light absorbed by a sample. In this experiment it is used to express the amount of the A, T, C, and G found after the paper chromatography.