Mesh : ABO Blood-Group System / chemistry genetics immunology physiology Adult Alleles Alternative Splicing Amino Acid Sequence Amino Acid Substitution Animals Evolution, Molecular Galactosyltransferases / genetics metabolism Gene Expression Regulation, Developmental Gene Frequency Glycosylation Humans Immunologic Surveillance / physiology Infant, Newborn Isoantibodies / immunology Mammals / blood genetics Molecular Sequence Data Mutagenesis, Site-Directed N-Acetylgalactosaminyltransferases / genetics metabolism Oligosaccharides / chemistry immunology Oligosaccharides, Branched-Chain Polymorphism, Genetic Species Specificity Substrate Specificity Trisaccharides / chemistry immunology