The invention concerns the introduction of predetermined genetic changes
in target genes of a living cell by introducing an oligodeoxynucleotide
encoding the predetermined change. The oligodeoxynucleotides are
effective in animal, plant and bacterial cells. Specific end
modifications that greatly increase the effectiveness of the
oligodeoxynucleotides in bacteria are described. Surprisingly, unmodified
oligodeoxynucleotides can be as effective in mammalian cells, including
in vivo hepatocytes, as the modified nucleotides and can be as effective
or more effective than chimeric oligonucleotides that consist of a
mixture of deoxynucleotides and 2'-O-methyl ribonucleotides.