In this thesis I have studied the biochemical machinery involved in targeting proteins to membranes, mediated by signal recognition particle (SRP), as well as components participating in translocation over membranes. Information about these components has been collected through analysis of genomic sequence data from Homo sapiens, Caenorhabditis elegans, Drosophilae melanogaster and Arabidopsis thaliana. Their genes have been identified, as well as the exon structure of these genes. I found that a majority of the proteins were encoded by single genes in the human genome. EST databases were screened for evidence of alternative splicing. An automated method for generating multiple alignments of EST sequences was developed so that frequent updates of the searches could be made. Evidence for alternative splicing was identified for the human genes of SRP9, SRP14, SRP19, Sec61 beta, Sec63 and Trap delta. The details of this investigation is present at