By Isaiah Heims and Noah Crumpton
Gregor Mendel’s experiments on peas demonstrate that heredity is transmitted in discrete units.
Frederick Miescher isolates DNA from cells for the first time and calls it “nuclein”.
Walter Flemming describes chromosome behavior during animal cell division. He stains chromosomes to observe them clearly and describes the whole process of mitosis in 1882.
Thomas Hunt Morgan and his students study fruit fly chromosomes. They show that chromosomes carry genes, and also discover genetic linkage.
William Astbury obtains the first X-ray diffraction pattern of DNA, which reveals that DNA must have a regular periodic structure. He suggests that nucleotide bases are stacked on top of each other.
Francis H. Crick and James D. Watson described the double helix structure of DNA.
Joe Hin Tjio defines 46 as the exact number of chromosomes in human cells.
Sydney Brenner, François Jacob and Matthew Meselson discover that mRNA takes information from DNA in the nucleus to the protein-making machinery in the cytoplasm.
The first finished, full-length sequence of a human chromosome is produced.
The finished human genome sequence will be at least 99.99% accurate.