The Central Dogma and Junk DNA
On September 19, 1957, Francis Crick delivered a lecture during a symposium at University College London, titled “Protein Synthesis”. The lecture was published a year later (1); in it, Crick quotes his colleague James Watson as saying, “The most significant thing about the nucleic acids is that we don’t know what they can do.” In contrast, Crick argued that proteins play a central, indispensable role as enzymes within the cell that catalyze a variety of chemical reactions. He believed that the main role of genetic material was to control the synthesis of proteins, although the mechanism of that process was not known.
Crick’s hypothesis came to be known as the central dogma of molecular biology, and it was immortalized in his hand-written notes that described the flow of information from DNA to RNA to proteins. This achievement was all the more remarkable, considering that messenger RNAs were completely unknown at that time, and very little was known about how the cellular translational machinery functioned within the cytoplasm to synthesize proteins. Although the later discovery of retroviruses appeared to challenge Crick’s central dogma, he explained quite succinctly that his original statement had simply been misunderstood, and that information could flow in both directions between DNA and RNA (2).
Continue reading “LncRNA: The Long and Short of “Junk RNA””
Science keeps on producing new discoveries every week. It can be difficult to keep up with the latest news even when it is part of your job. There were a few science stories that caught my attention this week so I thought I would share them.
“Galilean Thermometer Not So Galilean” was a surprising news item. I love my Galileo thermometer received as a Christmas gift several years ago. However, as Peter Loyson’s commentary in the Journal of Chemical Education points out, Galileo Galilei invented a thermometer but it was based on air. The one attributed to him was created by a Florentine group of academics and technicians founded by the Grand Duke Ferdinand II and his brother Leopoldo. And those first thermometers? Used wine to float the little glass balls.
Voyager 1, which just turned 35 on September 5, and Voyager 2 are pushing at the boundaries of our solar system as well as our understanding of space. In fact, NASA is saying that Voyager 1 was expected to pass through the heliopause, the edge that defines the end of the influence of our sun and the beginning of true interstellar space, but recent data indicated that this edge is further than we imagined. In fact, it could lie seven years beyond Voyager 1’s current position, and the battery in each Voyager estimated to deplete between 2020 and 2025. Still, these two small satellites have boldly gone beyond their initial mission to explore the far reaches of space and are still sending data back to our humble Earth.
Sequencing the human genome was an accomplishment but just this week, the scientists involved in the Encyclopedia of DNA Elements (ENCODE) project published 30 papers in Nature and other journals (summarized here). With the complete human sequence in hand, most scientists thought the items of interest in the genome were the genes, the coding regions. But as researchers started to dig into the data and use it for their experiments, it became evident understanding the genome was more complex than the sequence. The ENCODE project is a consortium of scientists that wanted to understand the entire genome and ended up finding that the 2% that encodes proteins is controlled by those sequences between genes nicknamed “junk DNA”. It is an incredible effort that has implications across aging and cancer, and ENCODE claims it can assign functions to 80% of the genome.