Interferon alpha 2b but not interferon alpha 2a detected in human genomic DNA.

The presence of the genes for human interferon (IFN)-alpha 2a and IFN-alpha 2b subvariants in human genomic DNA was studied using polymerase chain reaction (PCR). The respective genes differ in the coding sequence only at the position 137, adenine (2A) being substituted by guanine (2B). IFN-alpha 2-sequences were selectively amplified from the placental genomic DNA using specific primers. When sequencing the mixture of PCR-derived clones, at the position 137 guanine, specific for subvariant 2b could be detected. This indicates that, at least in the genome analyzed, only sequence coding for IFN-alpha 2b was found. Our finding supports the view, that genes for IFN-alpha 2a and IFN-alpha 2b seem to be rather allelic than occurring at distinct loci.