Entry courtesy of
The National Human Genome Research Institute (NHGRI)

Ribonucleic acid (RNA)

A chemical similar to a single strand of DNA. In RNA, the letter U, which stands for uracil, is substituted for T in the genetic code. RNA delivers DNA's genetic message to the cytoplasm of a cell where proteins are made.

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Dr. Leslie Biesecker, of the National Human Genome Research Institute's Laboratory of Genetic Disease Research, defines RNA.