1865 - Gregor Mendel

1909 - Wilhelm Johannsen (coined the term "gene," replacing Mendel's word "factor")

1911 - Thomas Hunt Morgan (proved chromosomes contained genes)

1939 - Rosalind Franklin, as a 19-year-old student, made the first sketch of a nucleic acid in the shape of a helix.

1943 - Osward Avery (Suggested genes are made of DNA, not protein)

1944 - Barbara McClintock (Some genes aren't fixed on chromosomes, but can move around as "jumping genes")

1952 - Hershey and Chase (Genes ARE DNA)

1953 - Watson and Crick (DNA's structure is a double helix)

1957 - Elliot Volkin & Lazarus Astrachan (RNA involved in the making of proteins)

1961 - Sydney Brenner (RNA acts as a messenger in the making of proteins)

1961 - Marshall Nirenberg (discovered codons code for amino acids)

1968 - Hamilton Smith (discovered restriction enzymes that can snip pieces of DNA)

1973 - Stanley Cohen & Herbert Boyer (a gene from a virus can be snipped out and pasted in bacteria)

1975 - Fred Sanger (invented a way to sequence long DNA sequences)

1977 - Phillip Sharp & Richard Roberts (within genes are long pieces of unused DNA)

1981 - Frank Costantini & Elizabeth Lacy (injected rabbit genes into fertilized eggs of mice & created the first "transgenic" mammal)

1983 - Kary Mullis (invented a fast and cheap way of making lots of copies of a small piece of DNA)

1986 - Leroy Hood (invented the first automated DNA sequencing machine)

1990 - Human Genome Project (a number of scientists undertook the project of sequencing the entire human genome)

2000 - Human Genome Project (the first draft of the human genome completed)