An allele is a variant of nucleotide sequence at a specific DNA locus. Alleles can differ through single nucleotide polymorphisms or insertions/deletions. Most alleles have minimal effect on gene function
Kell antigen system determines blood type and targets for autoimmune diseases. System includes K, k, Kpa, Kpb, Jsa and Jsb antigens. Kell protein is a 93-kilodalton zinc-dependent endopeptidase. KEL gene encodes type II transmembrane glycoprotein
ISBT defines blood group systems as controlled by single or closely linked genes. As of December 2022, 44 human blood group systems exist. Systems include ABO, Rh, and other antigens
Rh blood group contains proteins on red blood cell surface. System consists of over 50 antigens, with D, C, c, E, and e being most prominent. Rh(D) status described as positive (+) or negative (-) after ABO type. Two main nomenclature systems exist: Fisher-Race (CDE) and Wiener (Rh-Hr)
About one-third of people don't know their blood type. Blood type can be determined through Punnett Squares or blood type calculator. Rh factor is determined by both parents' blood types
AB+ blood is universal recipient, O- blood is universal donor. Only 7% of population has O- blood. Blood types determined by presence or absence of A or B antigens. Rh factor determines positive or negative blood type