Genetics Timeline


Watson and Crick Discover The Structure of DNA

1953 - 1954

The Number of Human Chromosomes is discovered

1955 - 1956

Jon Hin Tijo discovers that a human being has 46 chromosomes.

DNA is proven to be Semi-Conservative

1958 - 1959

Meselson and Stahl proved that DNA replication is Semi-Conservative. What this means is that each DNA is one new strand and one old strand.

RNA is Found to be the Intermediate Between DNA and Protein

1959 - 1960

What that means is that RNA copies the DNA segments from the nucleus and brings them to the cytoplasm to be made into proteins.

The Genetic Code is Cracked

1966 - 1967

Nirenberg, Khorana, and Ochoa figured out the genetic code.

Recombinant DNA is first constructed by Cohen and Boyer

1972 - 1974

Recombinant DNA is DNA that is created from two different organisms to make sequences that wouldn't occur normally. They are known as Chimeric DNA.

Kary Mullis Invents PCR

1986 - 1987

PCR (Polymerase Chain Reaction) is a technique used to make copies of a single gene. PCR is the (not really) process that involves heating up DNA so the two strands separate and grow back into two seperate strands of DNA, which recreates the process that happens in Mitosis

Various Genome Projects are Started and Finished

1990 - 2000

Genome projects are begun. The yeast genome is complete in 1996, and the C. elegans genome is done in 1998.

Amniocentisis Developed

1992 - 1993

Amniocentesis is the technique to test embryos for genetic abnormalities.

Genetically Engineered Tomatoes are Marketed

1993 - 1994

FlavrSavr tomatoes, which are genetically engineered so that they have a longer shelf life are marketed and sold.

Dolly The Sheep is a Successful Clone

1996 - 1997

After 277 failed attempts, Dolly the Sheep is born.

The Human Genome is Released

2001 - 2002

In reality only around 99% of the genome has been mapped. The last 1% is impossible to map without advances in technology.