MOLECULAR EVOLUTION OF CDC2 PSEUDOGENES IN SPRUCE (PICEA)

The p34(cdc2) protein and other cyclin-dependent protein kinases (CDK) are important regulators of eukaryotic cell cycle progression. We hav e previously cloned a functional cdc2 gene from Picea abies and found it to be part of a family of related sequences, largely consisting of pseudogenes. We now report on the isolation of partial cdc2 pseudogene s from Picea engelmannii and Picea sitchensis, as well as partial func tional cdc2 sequences from I? engelmannii, P. sitchensis and Pinus con torta. A high level of conservation between species was detected for t hese sequences. Phylogenetic analyses of pseudogene and functional cdc 2 sequences, as well as the presence of shared insertions or deletions , support the division of most of the cdc2 pseudogenes into two subfam ilies. New cdc2 pseudogenes appear to have been formed in Picea at a m uch higher rate than they have been obliterated by neutral mutations. The pattern of nucleotide changes in the cdc2 pseudogenes, as compared to a presumed ancestral functional cdc2 gene, was similar to that pre viously found in mammalian pseudogenes, with a strong bias for the tra nsitions C to T and G to A, and the transversions C to A and G to T.