title: Evolutionary analysis of the multigene pregnancy-specific beta 1-glycoprotein family: separation of historical and nonhistorical signals.
abstract: The pregnancy-specific beta 1-glycoproteins (PSG) form a large family of closely related proteins. Using newly developed methods of sequence analysis, in combination with protein modeling, we provide a framework for investigating the evolution and biological function of genes like the PSG. Evolutionary trees, based on C-terminal sequence, group PSG genes in a manner consistent with their genomic organization. Trees constructed using the N-terminal domain sequences are unreliable as an indicator of phylogeny because of non-neutral processes of sequence change. During duplication of the PSG genes, evolutionary pressures have resulted in a gradient of constrained change across each gene. The N-terminal domains show a nonrandom pattern of amino acid substitutions clustered in the immunoglobulin complementarity-determining region (CDR)-like regions, which appear to be important in the function of the protein.
authors.affiliation: Department of Microbiology and Genetics, Massey University, Palmerston North, New Zealand.
authors.forename: P A
authors.initials: PA
authors.lastname: McLenachan
authors.forename: P J
authors.initials: PJ
authors.lastname: Lockhart
authors.forename: H R
authors.initials: HR
authors.lastname: Faber
authors.forename: B C
authors.initials: BC
authors.lastname: Mansfield
mesh_terms: D002272:Carcinoembryonic Antigen / Q000235:genetics; D019143:Evolution, Molecular; D005260:Female; D014644:Genetic Variation; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D005810:Multigene Family; D010802:Phylogeny; D011247:Pregnancy; D011268:Pregnancy-Specific beta 1-Glycoproteins / Q000737:chemistry / Q000235:genetics*
chemical_list: D002272:Carcinoembryonic Antigen; D011268:Pregnancy-Specific beta 1-Glycoproteins