FOR IMMEDIATE RELEASE
Tracking Down the Mystery of Life’s ‘Handedness’
NYU-Poly Research Proposes a Theory on the Chemical Origin of Life:
‘Two Equal Runners, One Tripped’
NEW YORK, March 18, 2010 – Within the general question of the chemical origin of life lies
the question of handedness, or chirality (a term derived from the Greek word for hand). Critically
important molecules that make up life — including DNA, RNA, polysaccharides and proteins —
are chiral. This means there are mirror image forms that are not identical, much as one’s left and
right hands are different and are mirror reflections.
“The molecules of life have mirror images, which can be synthesized by organic chemists, but
the mirror images don’t exist in life any more than a person’s mirror image does,” explains Mark
M. Green, professor of chemistry at Polytechnic Institute of New York University (NYU-Poly).
But why should this be the case? Scientists have tried to answer this for many years.
One theory is that at the very beginning, there existed both mirror forms of the molecules that
would lead to life, but with a tiny excess of perhaps one extra left-handed molecule in a hundred
or even a thousand or more right- and left-handed molecules. If that small excess gets amplified
or concentrated, the mirror form that’s in excess could reasonably become the basis of the
chirality in the life that evolved. “Ronald Breslow at Columbia University has recently supported
this idea by discovering chemistry mechanisms in which tiny excesses of the chirality seen in
meteors raining down on earth, prevailed to control all of the chirality in life we see today,” says
Green.
Green recently showed how the properties of polymers support a different theory. In a paper with
his student Vipul Jain, featured in an “Editor’s Choice” section of the scholarly journal Science,
he proposed that both mirror forms of primordial life could have begun the evolutionary path but
that random events led to the survival of only one of these living mirror images. Green calls the
theory “Two Equal Runners, One Tripped.”
- more -
2
“It’s possible that life originated with both forms, and one died out and the other continued,” he
says.
This theory arises from knowledge of the behavior of polymers, first gained from Green’s
participation in the Polymer Research Institute, which was founded at Polytechnic Institute of
Brooklyn (now NYU-Poly) in 1946 by Herman F. Mark, who is known as “the father of polymer
science.” Moreover, when Green looked back in the records of the Institute, he discovered that
Nobel Prize winner George Wald had lectured in the 1950s at Poly and proposed the same idea:
that the primordial molecules of life originated in both mirror forms. Wald discussed his idea
with Albert Einstein, who suggested that there could have been a struggle between left and right,
parallel to a possible “fight” between negative and positive electrons. Wald even suggested that
when our species finally gets around to investigating other planets, humans will discover life on
the opposite side of the mirror from our own. Many years ago another distinguished scientist,
Hans Kuhn, suggested that fossils of early life might yield evidence of mirror image life.
When there are chiral choices to be made, life virtually always chooses one mirror form over the
other, never both -- although there are rare exceptions, Green says. Making the molecules that
life depends on of a single mirror form, or homochirality, allows for predictable and efficient
behavior. Moreover, natural polymers are more stable when they are made of chains of
molecules that are entirely left- or entirely right-handed. However, Green points out that
homochiral life on both sides of the mirror could have co-existed.
After the thalidomide disaster of the late 1950s, the entire pharmaceutical industry was forced to
pay more attention to the fact that our bodies react differently to mirror-image molecules
(enantiomers). Both mirror images of thalidomide were marketed as a mixture of the two; some
worked as intended and relieved morning sickness during pregnancy, while their opposites
caused severe birth defects in thousands of babies around the world.
These days, pharmaceutical companies always consider whether mirror forms differ in their
effects. Some medications are able to utilize both mirror image forms. In the case of ibuprofen,
for example, the body is able to convert the mirror image that is not a pain killer to its mirror
image, the pain killer. The pharmaceutical industry can therefore market a mixture of
enantiomers of ibuprofen.
Chirality is important in all aspects of the physical sciences. It is one of the foundation
principles. Quite a bit depends on this property, which we see every time we glance at our hands.
Certainly it is a central principle of life.
- more -
POLYTECHNIC INSTITUTE OF NEW YORK UNIVERSITY
SIX METROTECH CENTER BROOKLYN, NY 11201
3
Vipul Jain undertook his doctoral research at NYU-Poly in Green’s group. He now works in the
advanced polymer research laboratories of Rohm and Haas.
Green’s research in polymers has been funded over the years by the National Science
Foundation, The Petroleum Research Fund of the American Chemical Society and by the Office
of Naval Research.
About Polytechnic Institute of New York University
Polytechnic Institute of New York University (formerly The Polytechnic Institute of Brooklyn),
an affiliate of New York University, is one of New York City’s most comprehensive schools of
engineering, applied sciences, technology, and research, and is rooted in a 156-year tradition of
invention, innovation, and entrepreneurship: i2e.
The institution, founded in 1854, is one of the nation’s oldest private engineering schools. In
addition to its main campus at MetroTech Center in downtown Brooklyn, it offers programs at
sites throughout the region and around the globe. NYU-Poly has centers in Long Island,
Manhattan and Westchester County; globally, it has programs in Israel, China and will be an
integral part of NYU's campus in Abu Dhabi opening in autumn 2010.
For more information, visit www.poly.edu.
For images: http://www.poly.edu/about/press/releases
# # #
Contact:
Kathleen Hamilton
718-260-3792 office
973-997-0416 mobile
[email protected]
POLYTECHNIC INSTITUTE OF NEW YORK UNIVERSITY
SIX METROTECH CENTER BROOKLYN, NY 11201