Bovine Carboxylesterases: Evidence for Two CES1 and Five Families of CES Genes on Chromosome 18.

Predicted bovine carboxylesterase (CES) protein and gene sequences were derived from bovine (Bos taurus) genomic sequence data. Two bovine CES1 genes (CES1.1 and CES1.2) were located on chromosome 18 encoding amino acid sequences that were 81% identical. Two forms of CES1.2 were also observed apparently caused by an indel polymorphism encoded at the C-terminus end. Two CES gene clusters were observed on chromosome 18: CES5-CES1.1-CES1.2 and CES2-CES3-CES6. Bovine CES1, CES2, CES3, CES5 and CES6 shared 39-45% identity with each other, but showed 71-76% identity with each of the five corresponding human CES family members. Phylogeny studies indicated that bovine CES genes originated from five ancestral gene duplication events which predated the eutherian mammalian common ancestor. In addition, a subsequent CES1 gene duplication event is proposed during mammalian evolution prior to the appearance of the Bovidae common ancestor ~ 20 MY ago.