Those findings apply to a single generation, yet they tug at the edges of evolutionary theory, in which species change slowly over millennia, not rapidly over the months or years of a single life. Charles Darwin’s process of natural selection holds that nature choses the best-adapted organisms to reproduce and survive in any given ecosystem. The process operates when DNA sequences mutate randomly, and organisms with the specific sequences best-adapted to the environment multiply and prevail – causing gene expression to shift. Yet as surely as the slow march of Darwinian evolution shapes life on Earth over aeons, scientists have found that epigenetic signals can work each day, and not just through methyl groups. Experience in the environment could also alter chromatin, the molecular matrix making up our chromosomes; RNA, the messenger molecules that translate genetic instructions from DNA into protein; and histones, the proteins involved in packaging and structuring the chromatin comprising the genes.
Bill Fulkerson on 24 Mar 20The synthesis of structurally complex organic molecules is the first task in the discovery of functional compounds needed for new technologies, including those in medicine and flexible electronics. Starting with relatively simple, purchasable reactants, the process involves sequences of chemical reactions in which the complexity of the molecules produced gradually increases with each step towards the final target. The sequences can be linear, or convergent (different parts of the target molecule are made in separate sequences and then joined together). To ensure that large amounts of the final product are prepared, each synthetic step must be high-yielding and reproducible, and must generate few side products.
