We wish to explore differences in the structure of two human tRNA genes, one coding for the tRNAmet which functions as the general initiator for eukaryotic protein synthesis and the other for the tRNAmet serving as a standard amino-acyl carrier. The genes are being isolated from a recombinant population of human fetal liver DNA cloned in phage Charon 4A. Screening of the "library" is accomplished by Benton-Davis technology using nucleic acid probes generated from cloned Xenopus tRNAmet fragments, 32p-labeled rabbit tRNA, and 35S-methionyl-tRNA. It is our expectation that basic structural features will distinguish two very similar gene products with totally divergent functions.