The evolution of the vertebrate immune system has always been a puzzle that excited both evolutionists and molecular biologists. How could a system evolve in which one’s body could produce many copies of a specific antibody, of which there are thousands of possible forms? There simply couldn’t be as many genes are there are antibodies we are capable of making! In a concise, three-page review in this week’s Science, John Travis does a superb job of tying together the history of work on the immune system with the recent excitement that its evolution hinged critically on a moveable genetic element (containing two important genes) acquired from another species — perhaps a virus. Travis also discussed the evolution of innate immunity — that immunity not produced by genetic recombination among existing genes.
The clear, engaging prose of this piece, combined with its evolutionary perspective, makes it a must-read for those of us who aren’t familiar with the latest work on this most enigmatic of molecular adaptations.
A cell eating invading bacteria (phagocytosis). From the Science article.