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Gregor Mendel
Mendel published his work on the theory of genetics, his findings were ignored until the 1900s. Mendel's laws represented a theory of particulate inheritance that described how the germ cells of most organisms transmit characteristics from one generation to the next. -
Boveri
Boveri discovered that, during fertilization, the nuclei of sperm and egg do not fuse, as previously thought. Rather, each contributes sets of chromosomes in equal numbers. With this study, this provoked great interest in the chromosomes. -
Theodor Boveri and Walton Sutton
Boveri and Sutton came to the same conclusion while they worked independently, that chromosomes could be shown to bear the material of heredity. -
Frans Janssen
Janssen published in La Cellule the first description of the chiasma structure. He observed that, of the four chromatids present at the chiasmata sites (at diplotene or anaphase of the first meiotic division), two crossed each other and two did not. -
Thomas Hunt Morgan
Morgan discovered the recombination frequency and crossing over of genes; he confirmed Mendelian laws of inheritance and the hypothesis that genes are located on chromosomes. -
Barbara McClintock
McClintock discovered that genes can jump around on chromosomes, showing that the genome is more dynamic than previously thought. She was awarded the Nobel Prize in Physiology or Medicine in 1983 for her discovery of genetic transportation. -
Francis Crick and James Watson
Crick and Watson co-discovered the double helix structure of DNA.
They discovered that the chemical structure of deoxyribonucleic acid (DNA) meets the unique requirements for a substance that encodes genetic information. -
Marshall Nirenberg
Nirenberg discovered the first "triplet"—a sequence of three bases of DNA that codes for one of the twenty amino acids that serve as the building blocks of proteins. Because of this, the entire genetic code was deciphered within five years.
