Why we outlive our ape ancestors

December 2, 2009

In spite of their genetic similarity to humans, chimpanzees and great apes have maximum lifespans that rarely exceed 50 years. The difference, explains USC Davis School of Gerontology Professor Caleb Finch, is that as humans evolved genes that enabled them to better adjust to levels of infection and inflammation and to the high cholesterol levels of their meat rich diets.

In the December issue of PNAS Early Edition, Finch reveals that these evolutionary genetic advantages, caused by slight differences in DNA sequencing and improvements in diet, make humans uniquely susceptible to diseases of aging such as cancer, heart disease and dementia when compared to other primates.

Finch, the ARCO & William F. Kieschnick Professor in the Neurobiology of Aging and a distinguished University Professor, argues that a major contributor to longevity for humans is the genes that adapt to higher exposure to inflammation.

"Over time, ingestion of red meat, particularly raw meat infected with parasites in the era before cooking, stimulates chronic inflammation that leads to some of the common diseases of aging," Finch said.

In addition to differences in diets between species of primates, humans evolved unique variants in a cholesterol transporting gene, apolipoprotein E, which also regulates inflammation and many aspects of aging in the brain and arteries.

ApoE3 is unique to humans and may be what Finch calls "a meat-adaptive gene" that has increased the human .

However, the minor allele, apoE4, when expressed in humans, can impair neuronal development, as well as shorten human lifespan by about four years and increase the risk of heart disease and Alzheimer disease by several-fold. ApoE4 carriers have higher totals of blood cholesterol, more oxidized blood lipids and early onset of coronary heart disease and Alzheimer's disease.

"The chimpanzee apoE functions more like the "good" apoE3, which contributes to low levels of heart disease and Alzheimer's," Finch said. Correspondingly, in captivity have unusually low levels of and Alzheimer-like changes during aging.

Finch hypothesizes that the expression of ApoE4 could be the result of the antagonistic pleiotropy theory of aging, in which genes selected to fight diseases in early life have adverse affects in later life.

"ApoeE may be a prototype for other that enabled the huge changes in lifespan, as well as brain size, despite our very unape-like meat-rich diets," Finch said. "Drugs being developed to alter activities of apoE4 may also enhance lifespan of apoE4 carriers."

Source: University of Southern California (news : web)

Explore further: Do you want fries with that, Mickey?

Related Stories

Do you want fries with that, Mickey?

January 30, 2008

Using mice as models, researchers at the Max Planck Institute for Evolutionary Anthropology traced some of the differences between humans and chimpanzees to differences in our diet. The findings appear in the January 30 issue ...

How the APOE gene can modify your risk for Alzheimer's disease

November 13, 2008

One of the hallmarks of the brain of an individual with Alzheimer disease is the accumulation of amyloid-beta peptide (A-beta), something that is believed to be toxic to many brain cells (specifically neurons) and to therefore ...

Recommended for you

Machine Translates Thoughts into Speech in Real Time

December 21, 2009

(PhysOrg.com) -- By implanting an electrode into the brain of a person with locked-in syndrome, scientists have demonstrated how to wirelessly transmit neural signals to a speech synthesizer. The "thought-to-speech" process ...

Quantum Theory May Explain Wishful Thinking

April 14, 2009

(PhysOrg.com) -- Humans don’t always make the most rational decisions. As studies have shown, even when logic and reasoning point in one direction, sometimes we chose the opposite route, motivated by personal bias or simply ...

0 comments

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.