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Gregor Mendel
Grew over 10,000 pea plants & kept track of progeny numbers and type. He tracked the segregation of parental genes and their appearance in the offspring as dominant or recessive traits, recognized there were mathematical patterns of inheritance from parents to offspring and in general, the fundamental laws of inheritance. He deduced that genes come in pairs, one from each parent, and act as distinct units. He had the Law of Segregation, the Law of Independent Assortment, and the Law of Dominance -
Frederick Miescher
He was published in his paper on nuclein for discovering and isolating a new chemical within the nucleus of a cell, now known as nuclein. This was discovered while he was studying the composition of white blood cells. -
Thomas Morgan Hunt
Conducted an experiment on fruit flies to discover variation within species. Developed proof of “chromosomal theory of hereditary” which led to learning on the idea of inheritance. -
Alfred Sturtevant
He constructed the first genetic map of a chromosome by calculating the cross-over percentages between certain traits, and then with these percentages he was able to determine the relative distances between the genes on the chromosome -
Frederick Griffith
Suggested that bacteria are capable of transferring genetic information through transformation, bacteria don’t have fixed and non-interchangeable qualities, experiment with mice in which he injected a dead cell into a mouse and observed that the mice still died of pneumonia, showing that the information could transfer -
Harriet Creighton & Barbara McClintock
Proved that the recombination of genes linked on a chromosome requires the physical exchange of segments of the chromosome with its homologous partner (corn) -
Oswald Avery (and MacLeod & McCarthy)
Proved that a gene is made of DNA, and that protein is not that chemical that makes up genetic molecules. -
Erwin Chargaff
Discovered irregularities within the known chemicals of DNA, which then showed hereditary connections to living species. Due to illness, he was unable to finish his work, but that allowed Watson to fully discover DNA. -
James Watson & Frances Crick
Discovered the double-helix (two strands twisted around each other, instead of one) structure strings of DNA. -
Rosalind Franklin
Worked for years and years trying to solve the DNA “mystery”, came very close and showed her X-ray pictures to Watson and Frances who then knew of the solution. Watson’s work was published in an article shortly after, where Franklin’s work was shown as a supporting article. Took actual DNA picture. -
Al Hershey & Martha Chase
Tracked the transfer of proteins and DNA between a virus and its host. They injected a radioactive substance into the virus that is found in DNA but not proteins so that they could track where it was, whether it was inside or outside the protein shell. Concluded that the protein shell was not necessary to the replication process. When bacteriophages infect bacteria, their DNA enters their host bacterial cells, but most of their protein does not. -
Joe Hin Tjio
Tijo used an advanced technique to separate the chromosomes from the nucleus of a cell so that he could examine them further under a microscope. Since he was able to isolate them better, he was able to accurately count the number of chromosomes and had the breakthrough that cells contain 46 chromosomes, arranged in 23 pairs. This information then later contributed to the research of Down Syndrome -
Meselson & Stahl
Proved that DNA replication is semiconservative, meaning that each strand of DNA was its own, and served as a template during the replication process. -
Ian Wilmut
Is known for his genetic engineering and specifically for his successful cloning experiment with his sheep, Dolly. This was done by extracting cells from a living sheep, manipulating the cells nucleus and hibernation points, and then re implanting the embryos into a surrogate sheep mother. -
Herb Boyer
Boyer, along with Stanley Cohen, started the path for genetic engineering by discovering a process to get bacteria to produce foreign proteins. -
Alec Jeffreys
Created techniques that allow for DNA fingerprinting and DNA profiling people which led the path for forensic science that is still being used today. -
J. Craig Venter
He and his team came up with a new whole genome shotgun technique called “Expressed Sequence Tags” in which complementary DNA is partially tagged using an automated DNA sequencing machine. This new technology allowed him to be the first to sequence the human genome in Haemophilus influenzae in 1995 and then became the first to transfect a cell with a synthetic genome