Watson-Crick rules
The normal base pairing rules for DNA and RNA: A pairs with T or U, and G pairs with C.

Weigle reactivation
The increased survival of phage after UV irradiation if they infect cells that have previously been exposed to a lose dose of UV. Due to induction of UV repair systems in the infected cells.

Western blot
Transfer of proteins from an acrylamide gel onto a membrane filter for the detection with specific antibodies.

Wild-type
A strain used as a standard reference to compare any mutant derivatives. A wild-type strain may have certain nutritional requirements depending upon the species. Often a wild-type strain is simply one of the most convient strains of a particular species obtained from nature.

Wobble
A hypothesis proposed by Francis Crick to explain how one tRNA may recognize two different codons that differ in the third position. The three bases in the anticodon of each tRNA are antiparallel to the three bases of the codon in the mRNA. Normal Watson-Crick base pairing occurs between the first two bases of the codon with the complementary bases of the anticodon. However, the first (5') base of the anticodon can pair with the third (3') base of the codon in different ways: in this position of the anticodon G can pair with either C or U in the mRNA, U can pair with either A or G in the mRNA, and I can pair with A, C, or U in the mRNA.