Which of the following is the correct nomenclature of a restriction enzyme obtained from the first activity of strain R of Escherichia coli?
A. EcoR1
B. EscRI
C. EcorI
D. EcoRI
Explanation: The first letter is the first letter of the genus and the next two letters are the first two letters of the species. They are then followed by the strain and the activity from which they are isolated. The activity is represented in Roman numerals.