Function
This gene encodes a protein related to the first discovered blood group system, ABO. Which allele is present in an individual determines the blood group. The 'O' blood group is caused by a deletion of guanine-258 in the gene which corresponds to a region near the N-terminus of the protein. This results in a frameshift and translation of an almost entirely different protein. This mutation results in a protein unable to modify oligosaccharides which end in fucose linked to galactose. This sugar combination is termed the H antigen.
The A and B alleles of the ABO gene express enzymes with glycosyltransferase activities that differ, adding either N-acetyl galactosamine or galactose to the H antigen, converting it into the A or B antigen respectively. Individuals who are heterozygous for this gene express both proteins and so make both A and B antigens. Their blood group is AB. Remarkably, the difference between the A and B glycosyltransferase enzymes is only four amino acids. Other minor alleles have been found for this gene.
Read more about this topic: ABO (gene)
Famous quotes containing the word function:
“If the children and youth of a nation are afforded opportunity to develop their capacities to the fullest, if they are given the knowledge to understand the world and the wisdom to change it, then the prospects for the future are bright. In contrast, a society which neglects its children, however well it may function in other respects, risks eventual disorganization and demise.”
—Urie Bronfenbrenner (b. 1917)
“Every boy was supposed to come into the world equipped with a father whose prime function was to be our father and show us how to be men. He can escape us, but we can never escape him. Present or absent, dead or alive, real or imagined, our father is the main man in our masculinity.”
—Frank Pittman (20th century)
“Morality and its victim, the mother—what a terrible picture! Is there indeed anything more terrible, more criminal, than our glorified sacred function of motherhood?”
—Emma Goldman (1869–1940)