CYP gene superfamily (cytochrome P450 genes)

The cytochrome P450 genes in mammals are
designated CYP genes. They make up a superfamily
of genes that resemble each other in
exon/intron structure and that code for similar
gene products. An evolutionary pedigree has
been derived based on comparisons of their
cDNA sequences. According to this pedigree,
the CYP gene family arose during the last 1500–
2000 million years. It is assumed that the CYP-2
family in particular developed in response to
toxic substances in plants that had to be detoxified
by animal organisms. At least 30 gene duplications
and gene conversions have led to an
unusually diverse repertoire of CYP genes.