Genetic Scientists Review

Miescher

ED: Used leukocyte cells to isolate and study a new material that was rich of phosphorus which he dubbed “nuclein”

Contribution: First to isolate nucleic acid.

Garrod

ED: Studied alkaptonuria (metabolic condition that leads to excessive urination) in patients, found that patients often had parents who were 1st cousins.

Contribution: Connected health conditions to hereditary & Mendel’s Law of Inheritance.

Muller

ED: Studied x-ray exposure in fruit flies and mated them, found that their progeny exhibited physical abnormalities and often died; mutations.

Contribution: Mutations can occur in rearrangements of the molecules in the chromosome, can be passed down generations.

Beadle & Tatum

ED: Exposed spores to x-rays and put colonies in minimal mediums w/o vitamins, found that some strains could not grow due to their synthesizing pathways were blocked by a mutation.

Contribution: Genes are responsible for the creation of enzymes; mutations can stop the creation.

Griffith

ED: Tested smooth & rough strains of streptococcus. The rough strain was not harmful for mice, while the smooth strain was. The smooth strain that was heat treated was also not harmful, but when used in combination with the rough strain, it was harmful for the mouse. Found that the smooth strain must have passed the virulent info to the rough strain to kill the mouse.

Contribution: Transforming principle, bacteria could transform information and evolve.

Avery, Macleod, & McCarthy

ED: Used rough and smooth strain of bacteria and put them in various solutions that either removed proteins, RNA, or DNA, and was given to mice. All the mice died except the mice that were given the solution of DNA removed.

Contribution: Found that DNA was being transformed in the transformation principle & contained genetic material.

Hershey & Chase

ED: Studied bacteriophage on a bacteria, blended them to separate the bacteria and the virus, and used phosphorus and sulfur isotopes.

Contribution: Further proved that DNA is the hereditary information of the cell.

Chargoff

ED: Used hydrolysis in salmon sperm. Removed purines and pyrimidines via paper chromatography, sulfuric acid, and formic acid. Identified them using UV absorption spectra.

Contribution: Found molar ratios of composition of DNA; A:T & G:C are 1:1, and purines=pyrimidines.

Pauling

ED: Used x-ray crystallography to theorize on the structure of DNA

Contribution: Mistakenly said that DNA was a triple helix.

Franklin

ED: Used X-ray crystallography to look at the 3D shape of A and B form of DNA.

Contribution: Showed that DNA was a double helix, Photo 51

Watson & Crick

ED: Combined previous research done by Franklin, Chargaff, and Pauling to determine the shape and structure of DNA

Contribution: Determined that DNA was a double helix w/ nitrogenous bases in the inside and phosphate on the outside.

Meselson & Stahl

ED: Studied DNA Replication in E-Coli, allowed DNA to replicate for several generations & then centrifuged the cells to see the distribution of it. Found that the DNA was mixed in the middle.

Contribution: DNA replication is semi-conservative, nitrogen is divided equally among replication.