On the Origin of Life
Stockholm, June 8-10, 2006
By Magdalena Eriksson
The question of how life originated engages most people but nobody knows the answer. Despite having several theories, scientists don’t even know if they have found the right track yet.
It is generally believed that the universe was formed between 10 and 15 billion years ago, and Earth about 4.5 billions years ago. Evidence from fossils suggests that life had appeared on Earth 3.5 billion years ago.
The question was the focus of the Nobel Workshop “On the Origin of Life,” which took place in June of 2006 in Stockholm, Sweden. Some 50 scientists covering a range of expertise, including geology, chemistry, biology, genetics and astronomy contributed.
“Addressing this question from a broad perspective of the chemical and biochemical environment offers a breeding ground for scientific creativity,” said George Cody, geophysicist from the Carnegie Institution of Washington D.C.
"Addressing this question ...offers a breeding ground for scientific creativity"
George Cody
One of the leading theories of how life started contends RNA, a cousin of DNA, as a plausible first basis of life. The RNA molecule has the capability both to carry genetic material and to carry out chemical reactions that enable the molecule to make copies of itself. The capacity of self renewal is considered one of the criteria of a living system. A living system must also have a metabolism, have the ability to adjust to changes in its environment and be enclosed by a barrier that defines it from its surrounding.
Jack Szostak of Harvard University described experiments in which building blocks of RNA enter very tiny soap bubble like capsules, reminiscent of the membranes surrounding a living cell, where the RNA pieces can assemble to form chains. He has previously demonstrated that RNA chains under suitable conditions can elongate without the help of other large molecules. It is, however, not clear how the building blocks of RNA might have formed.
Even though early life based on RNA may seem plausible, other forms of biology may have preceded it. “Peptides could have been important in an RNA world,” said Leslie Orgel from the Salk Institute for Biological Studies in San Diego, California.
At the time when life began, Earth was thought to have been an inhospitable planet without an atmosphere of oxygen where not even the continents had formed. It is also likely that the planet at the time endured intense and destructive radiation, and that comets and meteors bombarded its surface.
The first molecules of life were probably made from carbon, oxygen, hydrogen and possibly phosphorous. These elements may have reached sufficiently high concentration in hot springs where minerals and energy could accelerate chemical reactions that linked small molecules to form long chains with the ability to self replicate.
A few scenarios were also abolished from the table. For example, the oceans, where earlier speculations have thought life began, are now considered too dilute for life to occur. The scientists also agreed that lightning from thunderstorms, previously seen as a possible source of energy sparks that started life, would probably break rather than make molecules as complex as the ones required for life.
"Now we know that we don't know how life began"
Gustaf Arrhenius
The participants in the workshop did not reach any conclusive answers to how life originated but rather agreed that we need further studies, perhaps with input from scientists with yet other perspectives on the problem. For example the notion that chemical reactions occur on surfaces or in the pores of rocks or clays may prove interesting. There is still the possibility that life did not originate on Earth, but was brought here from another galaxy.
“Now we know that we don’t know how life began,” said Gustaf Arrhenius, geochemist from Scripps Institute of Oceanography in La Jolla, California, at the end of the conference.
Craig Venter, one of the lead scientists behind the sequencing of the human genome, presented a study of the rich variety of current life. He heads an expedition that collects samples of sea water from its route around the globe. His analysis of the organisms found at different locations show an enormous variety among simple bacteria.
Despite these wide variations, Venter and his colleagues have found that a few proteins occur in many of the organisms they have studied, and thus seem to be crucial for life. Finding the smallest common denominator of life may bring them closer to a picture of what components are necessary for life. In another undertaking, Venter is trying to design one such simplest possible organism from scratch. Were this to succeed, this synthetic life form could be manipulated to perform desirable tasks, for example to produce hydrogen gas as a safe and sustainable source of energy.
The question was the focus of the Nobel Workshop “On the Origin of Life,” which took place in June of 2006 in Stockholm, Sweden. Some 50 scientists covering a range of expertise, including geology, chemistry, biology, genetics and astronomy contributed.
“Addressing this question from a broad perspective of the chemical and biochemical environment offers a breeding ground for scientific creativity,” said George Cody, geophysicist from the Carnegie Institution of Washington D.C.
"Addressing this question ...offers a breeding ground for scientific creativity"
George Cody
One of the leading theories of how life started contends RNA, a cousin of DNA, as a plausible first basis of life. The RNA molecule has the capability both to carry genetic material and to carry out chemical reactions that enable the molecule to make copies of itself. The capacity of self renewal is considered one of the criteria of a living system. A living system must also have a metabolism, have the ability to adjust to changes in its environment and be enclosed by a barrier that defines it from its surrounding.
Jack Szostak of Harvard University described experiments in which building blocks of RNA enter very tiny soap bubble like capsules, reminiscent of the membranes surrounding a living cell, where the RNA pieces can assemble to form chains. He has previously demonstrated that RNA chains under suitable conditions can elongate without the help of other large molecules. It is, however, not clear how the building blocks of RNA might have formed.
Even though early life based on RNA may seem plausible, other forms of biology may have preceded it. “Peptides could have been important in an RNA world,” said Leslie Orgel from the Salk Institute for Biological Studies in San Diego, California.
At the time when life began, Earth was thought to have been an inhospitable planet without an atmosphere of oxygen where not even the continents had formed. It is also likely that the planet at the time endured intense and destructive radiation, and that comets and meteors bombarded its surface.
The first molecules of life were probably made from carbon, oxygen, hydrogen and possibly phosphorous. These elements may have reached sufficiently high concentration in hot springs where minerals and energy could accelerate chemical reactions that linked small molecules to form long chains with the ability to self replicate.
A few scenarios were also abolished from the table. For example, the oceans, where earlier speculations have thought life began, are now considered too dilute for life to occur. The scientists also agreed that lightning from thunderstorms, previously seen as a possible source of energy sparks that started life, would probably break rather than make molecules as complex as the ones required for life.
"Now we know that we don't know how life began"
Gustaf Arrhenius
The participants in the workshop did not reach any conclusive answers to how life originated but rather agreed that we need further studies, perhaps with input from scientists with yet other perspectives on the problem. For example the notion that chemical reactions occur on surfaces or in the pores of rocks or clays may prove interesting. There is still the possibility that life did not originate on Earth, but was brought here from another galaxy.
“Now we know that we don’t know how life began,” said Gustaf Arrhenius, geochemist from Scripps Institute of Oceanography in La Jolla, California, at the end of the conference.
Craig Venter, one of the lead scientists behind the sequencing of the human genome, presented a study of the rich variety of current life. He heads an expedition that collects samples of sea water from its route around the globe. His analysis of the organisms found at different locations show an enormous variety among simple bacteria.
Despite these wide variations, Venter and his colleagues have found that a few proteins occur in many of the organisms they have studied, and thus seem to be crucial for life. Finding the smallest common denominator of life may bring them closer to a picture of what components are necessary for life. In another undertaking, Venter is trying to design one such simplest possible organism from scratch. Were this to succeed, this synthetic life form could be manipulated to perform desirable tasks, for example to produce hydrogen gas as a safe and sustainable source of energy.
