Interferon-α2 Variants in the Human Genome

Variants of human leukocyte interferon α2 (IFN-α2a, α2b, and α2c) differ from each other by changes in their coding regions at nucleotide positions 137 and 170. As a result of these nucleotide variations, the DNA sequences of the three variants can be distinguished by selective restriction enzyme analysis. Human genomic DNA obtained from over 28,000 normal healthy individuals was used as templates in the polymerase chain reaction (PCR) to amplify the human IFN-α2 gene sequence. The resulting PCR products were analyzed with restriction nucleases to identify the specific IFN-α2 variant sequences present in the genomic DNA of the population examined. The results show that IFN-α2b was detected as the predominant species and IFN-α2c as a very minor species (<0.1%). The IFN-α2a gene was not detected in this population.