The researchers pinpointed the locations of three previously identified human CYP3A genes and identified one novel member of this gene family. The targeted region of chromosome 7 contains about 230,000 base pairs, and the analysis revealed three pseudogenes, according to a paper describing the research in Pharmacogenetics . Schematic organization of the human CYP3A gene locus on chromosome 7. Arrows indicate the orientation of the open reading frames of CYP3A genes. Unmarked rectangles depict the three CYP3A pseudogenes found within the locus.
Arrowheads indicate duplication boundaries within the locus.
Courtesy of Leszek Wojnowski Leszek Wojnowski, of Epidauros Biotechnologie AG, in Bernried, Germany, led the study. This variation that may determine whether a patient has a positive or adverse response to a drug. Cytochrome P450 enzymes are a defense mechanism that protects organisms from naturally occurring toxic chemicals. The enzymes can also transform nontoxic chemicals into reactive intermediates that are toxic or carcinogenic, according to a recent News and Views article in Nature Medicine . Wojnowski and colleagues sequenced approximately one thousand bacterial clones representing the chromosome region using Perkin Elmer Biosystems capillary 3700 DNA analyzers.