The “First Replicon” on Earth? A Chat With Virologist Ricardo Flores
I spoke recently with virologist Ricardo Flores, Research Professor of the Spanish Research Council at the Institute for Cellular and Molecular Plant Biology in Valencia, Spain. Flores thinks viruses may be “the most important faction of the [planet's] biomass” and that a viroid-like entity is a prime candidate for the first replicon on Earth. Viroids are subviral world parasites, non-protein coding RNAs. Excerpts of our interview follow.
Ricardo Flores: Studies of the ocean are now revealing a further diversity of life totally unexpected, as we have discovered that the number of viral particles there is extremely high. One cell can harbor many, many viral particles.
Viruses may be the most important faction of the biomass.
We know now that there is a subviral world, which was not realized for the first 70 years of the 20th century. . . . Viroids represent the smallest organisms in terms of size on the biological scale. Compared to the genome of the tobacco mosaic virus, the viroid genome is 20 times smaller. . . . The simplest is the oldest in evolutionary terms and viroids fit very well with this notion.
I consider a viroid-like entity actually a very good candidate for the first replicon that may have populated Earth at the beginning of life. This enthralling hypothesis was first proposed by Theodor Diener, the discoverer of viroids.
But when initial experiments on viroids were done in the 1970s, it was difficult to convince the scientific community something of that size with such peculiar properties would be able to replicate.
A viroid RNA, for instance, doesn’t code for any protein. It doesn’t need to go to ribosomes and instruct them to generate proteins. —> Read More