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Geneticists
Создана
Zachary Chapman
⟶ Обновлено 10 дек 2018 ⟶
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События
Hershey and Chase To determine whether DNA or proteins are the genetic material Used bacteriophages cultured in radioactively marked sulfur and phosphorus to infect cells, then used centrifugation to separate out the isotopes in the cells The cells contained marked phosphate, but not sulfur, meaning that DNA is the genetic material -
Watson and Crick To find the structure DNA and how it works Used Wilkins and Franklin's image of DNA in order to model the structure DNA has a double helix structure made of two chains in an anti-parallel structure connected by nucleotides that form base pairs with each other
Периоды
Mendel Investigating what happens in the transmission of hereditary traits Cross-bred homozygous green (dominant gene) and yellow (recessive gene) pea plants, then continued breeding the offspring for a total of 4 generations Inheritance of traits is determined by "units," which are now known as genes An offspring inherits one allele from each parent
Sutton, Boveri, and Morgan To determine the basis for genetic inheritance 1902 - Boveri studied reproduction in sea urchins, while Sutton was studying meiosis in sea creatures, specifically the fact that during meiosis, the number of chromosomes in sex cells is halved 1915 - Morgan studied heredity in fruit flies Chromosomes carry genes from one generation to the other, and a specific set of chromosomes is necessary for normal growth
Griffith and Avery To determine if DNA or proteins are responsible for genetic coding 1928 - While attempting to work towards a vaccine for pneumonia, Griffith tested if mice would survive when he injected different strains of the disease into them. The mice injected with a mixture of heat-killed viral pneumonia and live non-viral pneumonia unexpectedly died 1944 - Isolated the "transforming principle" from Griffith's experiment and then chemically tested it to rule out possibilities for what it could be
Chargaff To determine whether DNA is responsible for differences between species Used paper chromatography to isolate DNA, and then analyzed the nucleotides via spectrophotometry Ratios of A:T and G:C in DNA are always both 1:1 Different species have different ratios of A and T to G and C
Wilkins and Franklin To determine the structure of DNA Used X-Ray crystallography to image DNA Discovered the helical shape of DNA and that DNA contains two strands attached together by nitrogenous bases