This perception is incorrect, as there is no such thing as a “missing link” in human evolution, says Professor Berger in an informative video, released by Wits University. This research has been misinterpreted by some sectors, creating the idea that Australopithecus sediba might be the “missing link”. The fossils that were found 10 years ago by Palaeoathropologist, Professor Lee Berger of the University of the Witwatersrand, and his son Matthew, at Malapa in the Cradle of Human Kind in South Africa, has recently been described as the so-called “missing link” in human evolution, after the publication of new research by a team of international researchers that confirmed the unique species status of Sediba. One thing is clear, without DAP or something like it, Earth might still be a lifeless mud puddle.Australopithecus sediba: No such thing as a missing linkĪutralopithecus sediba is not the missing link that connects modern man to its more primitive ancestors. Or maybe it even arrived on the back of a meteorite forged by a far-off star. Phosphate-rich lava flows may have reacted with ammonia in the air to create DAP, or it could have been leached out of phosphate-containing minerals. Krishnamurthy is working with geochemists to identify potential sources of DAP in the distant geological past. “That’s thermodynamically an uphill task.”ĭAP gets around that problem by removing a molecule of ammonia instead of water. “How do you remove water from a molecule when you are surrounded by a pool of water?” asked Krishnamurthy. For most phosphorylation reactions to work, they need to remove a molecule of water in the process.

He synthesized the molecule in his lab as a way to solve one of the fundamental challenges to phosphorylating in wet, early Earth conditions. RELATED: Life on Earth May Have Started With a Cosmic Splashįor one thing, Krishnamurthy has no proof that DAP even existed four billion years ago. We can’t make a claim that this is the way that life formed on the early Earth.” “The best we can do is try to demonstrate that simple chemicals under the right conditions could give rise to further chemistry which may lead to life-like behavior. DAP, Krishnamurthy found, could do it all, phosphorylating the four nucleoside building blocks of RNA, then short RNA-like strands, then fatty acids, lipids, and peptide chains.ĭoes that mean that DAP is the pixie dust that transformed random matter into life? Not quite, said Krishnamurthy. Past candidates for origin-of-life enzymes could only phosphorylate certain structures under wildly different chemical and environmental conditions. They combined DAP with different concentrations of magnesium, zinc, and a compound called imidazole that acted as a catalyst to speed the reactions, which still took weeks or sometimes months to complete.įor DAP to pass the test, it had to successfully trigger phosphorylation events that resulted in simple nucleotides, peptides, and cell wall structures under similar conditions. To test his theory, Krishnamurthy and his colleagues simulated early Earth conditions in the lab, using both a water base and a muddy paste set to varying pH levels. DAP may have been one of the first primordial kinases to get the phosphorylation ball rolling, Krishnamurthy believed. They use phosphorylation to send signals instructing cells to divide, to make more of one protein than another, to tell DNA strands to separate, or RNA to form. The enzymes that trigger phosphorylation are called kinases. So are sugars, amino acids, and proteins.”

“Your RNA, DNA, and a lot of your biomolecules are phosphorylated. “If you look at life today, and how it probably was at least three billion years ago, it was based on a lot of phosphorylation chemistry,” Krishnamurthy told Seeker. Without phosphorylation - which is simply the process of adding a phosphate molecule to another molecule - life wouldn't exist. For a number of years, his lab has been experimenting with a synthetic enzyme called diamidophosphate (DAP) that’s been shown to drive a critical chemical process called phosphorylation. Ramanarayanan Krishnamurthy is an associate professor of chemistry at Scripps and lead author of the origins of life paper.

Have they found the missing link