One of the most common misconceptions about Watson and Crick is that they discovered DNA (deoxyriboneucleic acid). DNA was discovered much earlier but not much was known about it. James Watson and Francis Crick proposed the double helix model for the chemical structure of DNA in 1953 after studying it at the cold spring harbor lab right here on Long Island.

Erwin Chargaff (above) came up with the theory that all base pairs in DNA must have a perfect 1:1 ratio. This rule will eventually become the basis for many DNA studies.

The base pairs in DNA only bind with other specific base pairs. A-T and G-C

Chromosomes are threadlike structures of DNA wrapped around a protein

A karyotype is a picture or diagram that shows all of the different types of chromosomes you can find in your body

There are two steps to DNA replication. In the first step an enzyme called helicase breaks down the hydrogen bonds holding the base pairs of DNA together. In the second step the DNA separates into a leading and lagging strand.

DNA damage can occur by a break in the DNA, missing bases from the backbone or a base can be chemically changed