Biology

Antibodies are shuffled, not stored

You have fewer than 20,000 genes, yet your body builds over a hundred billion antibodies, including ones for germs that do not exist yet. It stores no gene for each. As every immune cell matures, it randomly cuts and stitches one piece from each of three small groups of gene segments, so a small deck makes a vast library.

Sources & further reading

Nobel Prize Outreach (NobelPrize.org)The Nobel Prize in Physiology or Medicine 1987: Susumu TonegawaThe Nobel Prize for discovering that each immune cell builds its antibody gene by recombining separate segments.NCBI Bookshelf, National Library of Medicine (NIH)The Generation of Diversity in Immunoglobulins (Immunobiology, 5th ed.)The standard textbook account of how a few gene segments are shuffled into a vast antibody repertoire.Frontiers in Immunology (via PMC, National Library of Medicine / NIH)Secondary mechanisms of diversification in the human antibody repertoireThe paper with the segment counts and the layers of extra variety that reach over a hundred billion shapes.BMC Biology (BioMed Central)Open questions: How many genes do we have?The source for the human gene count being under about 20,000, the small number the antibody shuffle starts from.Nobel Prize Outreach (NobelPrize.org)The Nobel Prize in Chemistry 2018: Press Release (phage display)The Nobel Prize for the phage-display trick that copies the antibody shuffle in a test tube, behind drugs like Humira.PLOS BiologyRAG1 Core and V(D)J Recombination Signal Sequences Were Derived from Transib TransposonsThe study tracing the antibody-shuffling scissor back to an ancient piece of parasitic jumping DNA.