Principle of codification for quick comparisons with the entire biomolecule databanks and associated programs in FORTRAN 77

We propose a new method for homology search of nucleic acids or proteins in databanks. All the possible subsequences of a specific length in a sequence are converted into a code and stored in an indexed file (hash-coding). This preliminary work of codifying an entire bank is rather long but it enables an immediate access to all the sequence fragments of a given type. With our method a strict homology pattern of twenty nucleotides can be found for example in the Los Alamos bank (GENBANK) in less than 2 seconds. We can also use this data storage to considerably speed up the non-strict homology search programs and to write a program to help in the selection of nucleic acid hybridization probes.