Nobel Prize "for the discovery of introns".

Introns are fragments of DNA that are present in genes but do not encode information. Professor Roberts also discovered that genes may be discontinuous, meaning that a given gene may be present in separate segments of DNA. Originally this discovery was made in the DNA of the virus which leads to the common cold, the adenovirus, but soon it was found that these introns are common also in higher organisms, including humans.

The discovery was not only significant in its relation to the fundamentals of modern biology but was also extremely important in the field of medical research in relation to cancer and other diseases.