%0 Journal Article %T The evolutionary history of Cytochrome P450 genes in four filamentous Ascomycetes %A Jixin Deng %A Ignazio Carbone %A Ralph A Dean %J BMC Evolutionary Biology %D 2007 %I BioMed Central %R 10.1186/1471-2148-7-30 %X A total of 376 P450 genes were assigned to 168 families according to standard nomenclature. On average, only 1 to 2 genes per family were in each genome. To resolve conflicting results between different clustering analyses and standard family designation, a higher order relationship was formulated. 376 genes were clustered into 115 clans. Subsequently a novel approach based on parsimony was developed to build the evolutionary models. Based on these analyses, a core of 30 distinct clans of P450s was defined. The core clans experienced contraction in all four fungal lineages while new clans expanded in all with exception of NC. MG experienced more genes and clans gains compared to the other fungi. Parsimonious analyses unanimously supported one species topology for the four fungi.The four studied fungi exhibit unprecedented diversity in their P450omes in terms of coding sequence, intron-exon structures and genome locations, suggesting a complicated evolutionary history of P450s in filamentous Ascomycetes. Clan classification and a novel strategy were developed to study evolutionary history. Contraction of core clans and expansion of novel clans were identified. The exception was the NC lineage, which exhibited pure P450 gene loss.Fungi comprise a large and diverse kingdom of organisms. It is estimated that as many as 1.5 million species exist in the planet today [1,2]. Most described fungi grow by producing long, multi-celled hyphae, and are known as filamentous fungi. Filamentous fungi occupy a wide range of ecological niches with diverse life histories and physiological processes. Many live as saprotrophs decomposing and absorbing nutrients from dead materials while others have evolved the ability to be pathogens deriving their nutrients from living or dying hosts. Taking advantage of available genome sequences to explore the evolution of important gene families may help shed light on the processes that have allowed fungi to exploit diverse habitats.The P450-contain %U http://www.biomedcentral.com/1471-2148/7/30