Meeting Abstract

94.6  Friday, Jan. 7  Cytochrome P450 2B diversity in a wild rodent herbivore, the desert woodrat (Neotoma lepida) MALENKE, J.R.*; MAGNANOU, E. ; DEARING, M.D.; Univ. of Utah; Univ. of Utah; Univ. of Utah malenke@biology.utah.edu

Despite decades of work on the dietary habits of mammalian herbivores, there is little genetic information on detoxification genes in wild herbivores. Cytochromes (CYP) P450 are a large group of enzymes, many of which are involved in detoxification of xenobiotic compounds. Previous work on the desert woodrat (Neotoma lepida), an herbivorous rodent, suggested CYP2B plays a role in detoxification. To understand the role of CYP2B at a molecular level, we investigated its genetic architecture by sequencing and estimating gene copy number and compared this variability at the population level. We performed a feeding trial with two populations of woodrats that feed on different diets and compared CYP2B on reciprocal diet treatments. Using livers, we developed primers to sequence CYP2B cDNA and evaluated nucleotide and amino acid content from the sequences. We used a dereplication algorithm on the sequence dataset as well as genomic qPCR and Southern blotting to investigate CYP2B copy number. Our primers amplified a complete CYP2B transcript (1476bp) that BLASTed closest to norway rat CYP2B10. We recovered 39 unique cDNA sequences from 61 sequenced clones. When converted to amino acids, the average p-distance of the dataset was 0.0518. Both the cDNA and genomic copy number methods indicated that desert woodrats have at least 3 copies of CYP2B and up to 8 copies, similar to existing rodent species. Despite the variation, there were no differences in CYP2B sequence diversity, distribution or copy number between populations or experimental dietary treatments. The sequence diversity of CYP2B is likely due to the multiple gene copies as well as allelic diversity. The population comparison suggests that CYP2B may not be under selection for specialization with respect to diet.