Article Traces History of Darwinian Medicine

Dec 10, 2009

(PhysOrg.com) -- Despite being a founding principle of modern biology for 150 years, evolutionary theory has played a limited role in the field of medicine. Only in the last 20 years has Darwinian medicine emerged as a discipline unto itself. An article in this month’s issue of The Quarterly Review of Biology explains why early attempts to study disease from an evolutionary perspective failed, and how modern Darwinian medicine differs from its antecedent.

Attempts to link evolutionary theory and medicine were common among researchers from 1880 to 1940, according to author Fabio Zampieri, an of science at the University of Padua Medical School in Italy. But this early work in what Zampieri calls “medical Darwinism” was felled by fundamental misunderstandings of evolution. One such misunderstanding was the idea that human traits that cause disease had somehow escaped elimination by natural selection.

“Given that [diseases] were negative traits, it was natural to think that they ought to have been eliminated by natural selection,” Zampieri writes. “The fact of their persistence in the heredity and natural history of humans was necessarily proof that these characteristics could escape selective elimination.”

From that misunderstanding grew the idea the humans could intercede where natural selection had failed. We could artificially select “ideal” human types and discard the rest—a concept that became known as eugenics. The horrors of eugenics as applied in Nazi Germany brought the period of medical Darwinism to a screeching halt.

It wasn’t until the early 1990s that evolutionary theory began to once again be applied to medicine. But the new discipline of Darwinian medicine, which got its start and name from the work of biologists George Williams and Randolph Nesse, differs sharply from medical Darwinism.

Modern Darwinian medicine rejects the notion of an “ideal” human form or type, and understands that humans are very much the product of natural selection. Central to this new discipline is the idea that Darwinian adaptations often involve trade-offs—a positive trait can have negative consequences.

“The idea is that evolution does not shape disease, but only the anatomical, physiological, and psychological characters that can be vulnerable to disease,” Zampieri writes. “Most such characters are vulnerable because natural selection shapes optimal compromises, not perfection.”

A prime example of a Darwinian contribution to the understanding of disease is the case of sickle cell anemia. The disease is caused when a person receives two copies of a mutated gene—one from the father and the mother. A person who gets only one copy of the gene does not get the disease, but instead receives the advantage of malaria-resistant blood cells. So it’s clear why would tend to keep the mutated gene in the pool, despite the negative consequences for the individual who receives two copies.

A more recent application of Darwinian medicine is the association of allergies and cancer. In a review of the allergy-cancer connection in the December 2008 issue of The Quarterly Review of Biology, biologist Paul Sherman and colleagues found that allergy symptoms may have evolved as a kind of “smoke detector” that lets us know when carcinogens may be around.

Its explanatory power has helped Darwinian medicine develop into a promising new discipline, Zampieri concludes. And its better understanding of evolutionary theory makes a clean break from its flawed beginnings.

More information: Fabio Zampieri, "Medicine, Evolution, and Natural Selection: An Historical Overview." The Quarterly Review of Biology 84:4 (December 2009).

Provided by University of Chicago (news : web)

Explore further: A clear, molecular view of how human color vision evolved

add to favorites email to friend print save as pdf

Related Stories

Group selection, a theory whose time has come...again

Nov 28, 2007

Sociobiology, the discipline founded on Darwin's theory of group evolution, is in theoretical disarray. In a landmark article for the December issue of the Quarterly Review of Biology, eminent evolutionary scientists David ...

Study discovers secret of Scottish sheep evolution

Jan 17, 2008

Researchers from the University of Sheffield, as part of an international team, have discovered the secret of why dark sheep on a remote Scottish Island are mysteriously declining, seemingly contradicting Darwin’s evolutionary ...

Evolution Of Irreducible Complexity Explained

Apr 12, 2006

Using new techniques for resurrecting ancient genes, scientists have for the first time reconstructed the Darwinian evolution of an apparently "irreducibly complex" molecular system.

Disease resistance may be genetic

Aug 30, 2007

According to a study in Evolution, resistance to certain infectious diseases may be passed genetically from parent to child. The genetic resistance may be beneficial to families as those with the gene are both unlikely to suf ...

Recommended for you

Contrasting views of kin selection assessed

Dec 17, 2014

In an article to be published in the January issue of BioScience, two philosophers tackle one of the most divisive arguments in modern biology: the value of the theory of "kin selection."

Microbiome may have shaped early human populations

Dec 16, 2014

We humans have an exceptional age structure compared to other animals: Our children remain dependent on their parents for an unusually long period and our elderly live an extremely long time after they have ...

DNA sheds light on why largest lemurs disappeared

Dec 16, 2014

Ancient DNA extracted from the bones and teeth of giant lemurs that lived thousands of years ago in Madagascar may help explain why the giant lemurs went extinct. It also explains what factors make some surviving ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.