Piers
06-19-2007, 11:44 AM
Just read an interesting article in the June Scientific America by Robert Shapiro (http://www.sciam.com/article.cfm?articleID=B7AABF35-E7F2-99DF-309B8CEF02B5C4D7&pageNumber=1&catID=4) about the metabolism first approach to the origin of life.
Basically the idea seems to be that life started off as a repeating cycle of chemical reactions, which gradually got more complicated. No genetic material needed, the presence of the constituents contained all the malformation needed for reproduction.
Here is a key part of the article
[ QUOTE ]
An understanding of the initial steps leading to life would not reveal the specific events that led to the familiar DNA-RNA-protein-based organisms of today. However, because we know that evolution does not anticipate future events, we can presume that nucleotides first appeared in metabolism to serve some other purpose, perhaps as catalysts or as containers for the storage of chemical energy (the nucleotide ATP still serves this function today). Some chance event or circumstance may have led to the connection of nucleotides to form RNA. The most obvious function of RNA today is to serve as a structural element that assists in the formation of bonds between amino acids in the synthesis of proteins. The first RNAs may have served the same purpose, but without any preference for specific amino acids. Many further steps in evolution would be needed to "invent" the elaborate mechanisms for replication and specific protein synthesis that we observe in life today.
[/ QUOTE ]
Basically the idea seems to be that life started off as a repeating cycle of chemical reactions, which gradually got more complicated. No genetic material needed, the presence of the constituents contained all the malformation needed for reproduction.
Here is a key part of the article
[ QUOTE ]
An understanding of the initial steps leading to life would not reveal the specific events that led to the familiar DNA-RNA-protein-based organisms of today. However, because we know that evolution does not anticipate future events, we can presume that nucleotides first appeared in metabolism to serve some other purpose, perhaps as catalysts or as containers for the storage of chemical energy (the nucleotide ATP still serves this function today). Some chance event or circumstance may have led to the connection of nucleotides to form RNA. The most obvious function of RNA today is to serve as a structural element that assists in the formation of bonds between amino acids in the synthesis of proteins. The first RNAs may have served the same purpose, but without any preference for specific amino acids. Many further steps in evolution would be needed to "invent" the elaborate mechanisms for replication and specific protein synthesis that we observe in life today.
[/ QUOTE ]