ablation 1 (in surgery) the removal or destruction of tissue by a surgical procedure. 2 (in genetics) a technique for the removal of a tissue or a particular cell type during development. It depends on the tissue-specific expression of a toxin gene such as diphtheria A (dipA) in a transgenic organism.

abl an oncogene from murine Abelson leukemia virus. The human equivalent is ABL (locus at 9q34), which encodes a tyrosine protein kinase. In humans, inappropriate activation of ABL occurs via a reciprocal translocation between chromosomes 9 and 22 in which ABL is joined at the breakpoint cluster region (bcr) of the ph1 gene on chromosome

ABH antigens one of the systems of blood group antigens having determinants associated with oligosaccharide structures. It is the basis of the ABO system, which was the first human blood group antigen system to be detected, by Austrian-born US pathologist Karl Landsteiner (1868–1943) in 1901, and it remains the most important in blood transfusion. Individuals