Where and how did life begin? This is the ultimate question that biologists do not have definite answer amid advance technology.
Until recently, scientists believed that DNA, which is a molecule that contains life's unique genetic code, came from RNA molecules. However, a new study conducted by a team of researchers from the Scripps Research Institute (TSRI) made scientists question the RNA World Hypothesis, the prevalent theory on life's origin.
The RNA World Hypothesis states that the enzymes and proteins that are the foundation of life, came from self-replicating RNA, which is the result of various chemical reactions. The recent research, however, made scientists reevaluate this idea about the birth of life on Earth four billion years ago. Now, they are considering the possibility that DNA could have co-existed with RNA from the beginning.
Ramanarayanan Krishnamurthy, associate professor of chemistry at TSRI and senior author of the new study asked, "Why not think of RNA and DNA rising together, rather than trying to convert RNA to DNA by means of some fantastic chemistry at a prebiotic stage?"
Krishnamurthy acknowledged that this theory was already proposed before. Though not the first to propose, the findings on chimeric instability in his lab give scientists more evidence to support the theory.
Initially, scientists thought that RNA and DNA combined to form heterogeneous strands that would lead to "chimeras." The tests, however, revealed that the strands are unstable. This instability made scientists conclude that RNA and DNA could possibly evolve concurrently. Researchers said that the theory of DNA originating from RNA could still be possible; however, this could have happened after RNA met DNA and gathered its raw material.
Although scientists would have no way of knowing how exactly life began, Krishnamurthy believes that the knowledge of the early stage of evolution is important in the study of biology.
This study has been published in the journal Angewandte Chemie International Edition.
