Viroid Holds Clues to Early Evolution

A pathogen that stunts and disfigures potatoes and tomatoes, could shed light on the evolution of life on earth. It is a hundred times smaller than a virus and is called a viroid. The viroid has its genome content in a single strand of rna without the protective protein cover which viruses have. Scientists infected plants with a viroid in the laboratory and found that it had high rates of mutation due to errors during rna replication. They are unlike multi-cellular organisms like humans that can lower mutation rates and correct errors while the dna replicates. The study published in the March 6 issue of Science suggests that such replication errors could be the reason behind the diversity of organisms on earth because higher is the rate of mutation, more does a species evolve.

Source: Down To Earth, April 2009