Is evolution a series of little tweaks along a march of progress?Tobias Schwarz/Reuters
A different evolutionary narrative
But we cannot content ourselves with old narratives just because they are comfortable and familiar. Theoretical epidemiologist Sunetra Gupta presents the case that many infectious diseases, including influenza virus, evolve by the reassembly of old parts from disparate sources, not by a continuous evolutionary stroll somewhere new. Rather than a Blind Watchmaker tinkering with last year’s model – Richard Dawkins’ famous image of evolution – a Mad Scientist assembles new Frankensteins each year in his laboratory.
Certainly, the new flu vaccine you get each year does not sound like a link in a continuous chain; it’s more like a mixture of A/New Caledonia/20/99 and B/Shandong/7/97, blended from past disease strains. Gupta and her group at Oxford contrast the cozy classical notion of antigenic drift with antigenic thrift, which conjures the apposite image of rooting around in a charity shop to find old clothes to make a new outfit.
Which view of the evolution of the influenza virus is correct is currently the subject of active and contentious scientific study.
The point is that metaphors have great power in science. They’re not forced on us by reality, though.
The importance of powerful images for the public understanding of science cannot be overstated. Previously, the world press treated us to the Late Night Double Feature Picture Show of scientists digging up the graves of corpses in the Arctic permafrost to reanimate in the lab the deadly 1918 influenza virus that originally killed them. This remarkable flu study would likely have passed with less fanfare if not for the connection to popular myths. Thanks Mary Shelley!
But we must choose our metaphors wisely, lest we be misled. The Great Chain of Being, strung through evolutionary space by Blind Watchmakers, with missing links waiting to be discovered, isn’t going to help us understand infectious disease.
Sean Nee, Research Professor of Ecosystem Science and Management, Pennsylvania State University
This article was originally published on The Conversation. Read the original article.