cytosine
- n a base found in DNA and RNA and derived from pyrimidine; pairs with guanine
- Normally, humans have five to 55 repetitions of the nucleotides CGG (cytosine, guanine, guanine) in this region.
- Working with only the four basic nucleotides that make up all DNA adenine, cytosine, guanine and thymine he has assembled an entirely new chromosome for an entirely new one .
- He realized that "an adenine-thymine pair held together by two hydrogen bonds was identical in shape to a guanine-cytosine pair.