Is the Origin of Life in Hot Water?

Is origin of life chemistry in hot water? So it seems according to a new paper in the Proceedings of the National Academy of Sciences. The authors address the conundrum of origin of life chemists between the rate of (un-catalyzed) organic reactions and the lack of time available for these reactions to occur. From the article (note: an enzyme is a biological catalyst): Whereas enzyme reactions ordinarily occur in a matter of milliseconds, the same reactions proceed with half-lives of hundreds, thousands, or millions of years in the absence of a catalyst. Yet life is believed to have taken hold within the first 25% of Earth’s history. How could cellular chemistry and the enzymes that make life possible, have arisen Read More ›

Regulating DNA Repair Mechanisms

Every once in a while an article comes out on a new DNA repair mechanism or a new feature of a known DNA repair mechanism. There are so many complexities behind DNA repair and there is still more to uncover. Last October, a review article came out in Molecular Cell on regulatory factors for DNA repair mechanisms (Molecular Cell 40(2), October 22, 2010, 179-204). Basically, DNA repair mechanisms are very powerful because they can often replace or remove nucleotide bases. So these powerful mechanisms need something to make sure they do their job properly and not destroy the whole genome in the process. That is where regulators come in. If DNA repair mechanisms are medics flying out to the damaged Read More ›

The Human Genome Project Ten Years Later

Scientific American recently reported on what has transpired since the completion of the Human Genome Project ten years ago. When the HGP was first announced in 2000, many scientists said that it would be the key to understanding disease and for developing cures. Ten years later, however, this has not been the case. The human genome project has aided in developing better research and technology, particularly in our abilities to sequence genes. It has also shown us that much of what we once considered junk DNA isn’t really junk at all. (See here, here, here, and here for past ENV discussions on junk DNA). However, scientists are coming to a sobering conclusion that perhaps their models and assumptions on the Read More ›

A Chilling Origin of Life Scenario

The most popular of the Origin of Life (OOL) models is the RNA-first world. RNA can have catalytic properties similar to proteins (enzymes) and are thus called ribozymes. RNA or some form of pre-RNA is an attractive early earth molecule and possible progenitor to early life because, unlike the chicken-and-egg problem with proteins and DNA, theoretically, RNA replication can be completely self-contained. In fact, in January 2009 Nature reported on the synthesis of a self-replicating RNA molecule capable of catalyzing its own replication. See Casey Luskin’s report here. There are several problems with the RNA-first model (See here for a short discussion on some problems with RNA, and see Chapter 14 in Signature in the Cell) not the least of Read More ›