the DNA might have mixed with the RNA to produce the first life on Earth
Despite a failed attempt to create life in the laboratory, the scientists were able to learn that at the heart of life are two main forms of genetic code of the DNA molecule and RNA contained in the cells of all living organisms, being the basis of all earthly biology. According to a widespread hypothesis, RNA formed the basis of the Earth's biosphere long before there was DNA and other essential molecules. However, the difficulty of ribose and then its connection with the other molecules in conditions that presumably existed on the early Earth, is the main drawback of the idea of RNA. For this reason, scientists have searched for more likely ways of getting Robotnik sugars. As shown by the results of a new study of DNA and RNA could exist on the planet even before origin of life. But how is this possible?
Using a chemical system based on the hydrogen cyanide, is designed to simulate conditions on the early Earth, an international team of scientists from England, Scotland and Poland were the so-called «base» four molecular «letters» genetic alphabet. All together these bases form the genetic sequences of the cells are then transferred to proteins. As it turned out in several sequential experiments, two of the four resulting bases was discovered in the form of DNA, and the other two in the RNA. A study in the journal Nature.
The Work, led by John Sutherland from the Laboratory of molecular biology medical research Council in Cambridge further undermines the popular hypothesis of RNA in which the DNA appeared exactly thanks to the RNA. To date, however, have found little evidence that the chemical way of transformation of RNA can lead to the formation of DNA. People tend to think of RNA as the parent DNA. But the results suggest that DNA and RNA are molecular brothers and sisters, – said John Sutherland, the study's lead author.
Scientists are trying to figure out since the 1950-ies. That's when American scientists Stanley Miller and Harold Urey conducted a landmark experiment. The pair simulated the effects of lightning in the atmosphere and ocean of the early Earth, causing an electric discharge in a flask containing hydrogen, water, ammonia and methane. Although the experiment produced organic molecules, vital to the biochemistry, for decades, other researchers have discussed the plausibility of the conditions of the conducted experiment.
the Appearance of life on Earth – one of the main questions of modern science
However, the work of Miller and Urey showed that to important substances – such as amino acids, which are joined to form proteins, performs a variety of functions in living cells – is quite simple. Of particular importance for studies of the origin of life is the fact that proteins can act as catalysts, enhancing and speeding up other chemical reactions, which otherwise would be too slow or ineffective. And yet, squirrel is not the only possible catalysts for the emergence of life on Earth.
In the work that eventually brought scientists a Nobel prize in chemistry in 1989, molecular biologist Sidney Altman, biochemist Thomas Cech discovered that RNA has long been regarded as only an intermediate carrier of genetic information, subject DNA can also behave as a catalyst. The hypothesis of the RNA suggests that these molecules can replicate itself, providing early evolution before the advent of DNA and proteins. However, the idea of «RNA world» was overly enthusiastic reaction to a great opening weekend.
As Scientific American, to create long strands of DNA, base first, connect with «spine» sugar molecules. These combinations form the nucleosides: deoxyribonucleotides DNA and ribonucleotide in the RNA that form a single spiral. Nukes is glycosylamine containing nitrogenous base associated with sugar. Nucleosides do not use table sugar or sucrose, but the ribose in RNA and deoxyribose in DNA. The difference between the two types of sugar is very small: only one oxygen atom and one hydrogen atom. However, this difference is enough to DNA and RNA had a different biological role.
the Atoms that comprise all life on the planet, appeared in the explosion of supernovae
In the course of workscientists mixed some intermediate molecules from previous studies of salt – sodium nitrite, and magnesium chloride, which could be extended to primitive Earth, and then exposed them to acidic conditions and heat, respectively. Through these steps, the researchers found two possible ways to add a fourth reason – a less common nucleoside inosine. This was enough to create four-letter genetic alphabet, in which each base in the molecular chain interact exclusively with one of the other three letters in the second chain – work of modern RNA and DNA. But in the experiment, two letters came from RNA, and two of DNA.
As suggested by Sutherland, people tend to think that RNA precedes DNA, and then somehow captured it. This suggests that life could arise from the hybrid RNA-DNA, which then could give rise to two separate molecules. However, Sutherland's team have not yet collected individual nucleosides and ribonucleosides in a long chain. This is important because the demonstration that the hybrid strands can indeed be formed and contact with a partner thread, is crucial for on the Ground. Well, we wish the researchers good luck and we expect to continue research. What do you think, how and why life began on our planet?
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