Scientific results of the decade: life sciences rulezzz!

Decade of discoveries
Science magazine summed up the scientific results of the decade
Irina Yakutenko, <url>The staff of the news service of one of the most authoritative scientific journals – Science – presented a selection of the ten most significant trends, ideas and technological trends that have emerged over the past ten years (Insights of the Decade).

"The tape.<url>" offers a brief annotation to each of the items on this list, summarizing the symbolic outcome of the scientific development of the beginning of the XXI century.

The dark genomeIn 1869, Swiss researcher Johann Friedrich Mischer discovered DNA by isolating it from human leukocytes.

For the next 75 years, most scientists believed that the cell uses DNA to store phosphorus, but in 1944, Oswald Avery, Colin MacLeod and Maclean McCarthy conducted an experiment that clearly demonstrated that DNA is a carrier of genetic information (hints of this have been noticed before, but the experience of Avery, MacLeod and McCarthy finally proved the validity of such a hypothesis). In 1953, James Watson and Francis Crick determined the structure of the DNA molecule – now even people far from biology know that it is a double helix.

In 2001, for the first time, the complete human genome was deciphered – more precisely, the collective genome of three people at once. From that moment on, a new era began in molecular biology, as researchers gained access to all the "instructions" by which living systems function. As the technology of decoding and copying DNA fragments improved, scientists accumulated incredible amounts of genetic data, the analysis of which led to a paradoxical conclusion: the so-called "junk DNA", which was considered an unnecessary ballast, plays a huge role in controlling the work of the cell.

In addition, biologists have found out that a lot of instructions indicating "how to live on" do not come from DNA at all, but from relatively simple add-ons that are attached to individual "letters" of the genome (this type of regulation was called epigenetic regulation). Finally, the third group of "puppeteers" of the cell turned out to be RNA molecules, which are synthesized from the most unexpected parts of the genome and control metabolism no worse than proteins. These three types of non-canonical cellular "managers" are united under the general name of genomic dark matter or simply the dark genome. Over the past 10 years, scientists have become convinced that this genome is at least as important as the "ordinary" one.

The Rebirth of CosmologyAstronomy is fundamentally different from other natural sciences in that it is impossible to set up an experiment to test a hypothesis.

All astronomers can do is observe the sky and make assumptions that would explain what they saw. At first, there were a lot of such assumptions: scientists had not very much not very accurate data at their disposal, and with the proper development of imagination, they could be combined in any way into more or less coherent pictures of the organization of the Universe.

But as technology has evolved, instruments have become more accurate, data collection methods have become more sophisticated and reliable, and the computers with which this data is analyzed have become more powerful. Gradually, the number of possible explanations for the structure of the Universe in general or individual types of stars in particular began to decrease, and today we can say that a logical theory has developed in astronomy, which includes all stages of the Universe's development from its birth to the appearance of the planet Earth. And although there are still many white spots in this theory (in particular, the first moments after the Big Bang remain mysterious), in general, it is consistent and leaves no room for speculation that deviates too much from the general line.

Improving methods of working with ancient DNAFor a long time, paleontologists received information about the appearance and lifestyle of extinct living creatures only on the basis of studying fossilized bones and tools (if we were talking about hominids).

With such a meager source material on hand, paleontologists, nevertheless, were able to reconstruct extensive fragments of the past in detail and compile very complex evolutionary trees. Today, with the help of computer models and comparisons with related species, scientists are able to restore the appearance of creatures from a single bone, although the result is not always reliable.

But in recent years, paleontologists have a new incredibly powerful analysis tool that biologists have given them. The latter have learned to isolate DNA from almost anything and determine its sequence even when only a few deoxyribonucleic acid molecules are present in the sample. These methods proved to be extremely in demand in paleontology – suddenly it turned out that DNA can be preserved in fossilized remains for hundreds of thousands of years.

For several years, scientists have isolated and studied the DNA of mammoths (based on the results of the analysis, the researchers clarified the evolutionary relationship of mammoths with elephants and, for example, found out that among the ancient hairy proboscis there were brunettes, blondes and redheads), deciphered the Neanderthal genome and established that the genes of Homo neanderthalensis are in each of us, found the remains of a new species of people which were initially mistaken for the remains of "ordinary" Neanderthals, and did a lot more. The development of methods of working with ancient DNA has brought paleontology to a qualitatively new level, so new discoveries should be expected in the next decade.

Water on MarsMars, the fourth planet of the Solar System, has been attracting the attention of scientists for a very long time.

Firstly, it is relatively close to Earth, and therefore it is convenient to study it, and secondly, Mars resembles our planet in many ways - after all, it is always more interesting to explore something that looks like you. In the case of Mars, the situation is even more intriguing, because the similarity to Earth automatically means a good chance of habitability, at least in the past. For the existence of terrestrial organisms, water in liquid form is necessary, so scientists have been trying hard to find it on the Red Planet. Most experts agreed that there is no liquid water on Mars these days, but a few billion – or maybe even millions – years ago, it was quite possible that it was there.

Numerous orbiters and landers have collected a lot of indirect evidence of the presence of water on Mars (mainly, it was data on the relief of the planet formed by water, and about the "suspicious" composition of Martian minerals), but the first really serious argument in favor of the hypothesis about the wet past of Mars was discovered by the Mars Odyssey orbital probe. The data he collected indicated that there were deposits of water ice under the surface of the Red Planet. Later, this assumption was confirmed by other apparatuses, but finally the question of the presence of water on Mars was resolved in 2008, when the Phoenix probe, which landed near the north pole of the planet, received H2O from the Martian soil by heating it in a built-in furnace. So one of the sacramental problems of the Red Planet has now been solved, and in the future scientists will have to find out if there is life on Mars when exactly liquid water disappeared from the surface of Mars.

Reprogramming cellsThe organism of any living being consists of cells (or at least one cell).

In complex multicellular organisms, different cells are not similar to each other and perform completely different functions. But each of them initially contains data that allows it to become any other cell of the body. These data are recorded in DNA, which is the same in all cells of the body (with the exception of germ cells). The differences in appearance and behavior are explained by the fact that some genes work in skin cells, while the cells of, say, the pancreas have completely different ones.

All cells of the body have a common origin – their "foremother" is an egg, whose descendants carry copies of its DNA. Unlike most cells, which perform strictly defined functions and generate only the same highly specialized "children", the descendants of an egg can become anyone. Scientists have long suggested that under certain conditions, any cell of the body can return to its "pristine" state – that is, gain the ability to produce cells that are not similar to themselves (scientists use the term dedifferentiate), but for a long time there was no actual confirmation of this hypothesis from researchers.

Over the past ten years, biologists have learned some "cellular transformations". So, scientists have found out that cells can dedifferentiate when several specific genes are introduced into their genome. In addition, you can make the cell forget about its narrow specialization with the help of a special protein cocktail. Artificially dedifferentiated cells should help scientists and physicians find new therapies for diseases associated with cell death (for example, Alzheimer's disease), as well as change the approach to transplantation – organs for transplantation grown from the patient's own cells will not be rejected.

MicrobiomeThe fact that there are many bacteria living in the human body has not been news for at least a hundred years.

However, the exact number of microscopic human roommates remained unknown. In recent years, it has become clear that the number of bacterial cells is an order of magnitude greater than the number of actual cells of the body – that is, out of every ten cells of our body, nine are bacterial. The collective genome of all microorganisms living in humans is called the "microbiome".

Most of the bacteria living inside and outside the body do not harm it, and some also help in performing the most necessary actions (for example, normal digestion is impossible without bacteria living in the digestive tract), but in recent years scientists have learned a lot of much more interesting facts about our "neighbors".

Firstly, thanks to effective and, most importantly, cheap technologies for decoding and copying DNA, researchers were able to clarify the question of which bacteria inhabit our body. It turned out that on each part of the body, due to different conditions in neighboring areas (for example, on two fingers of one hand), different populations of microorganisms live.

In addition, it turned out that bacteria can at least partially determine many features of people who, at first glance, are not related to bacteria in any way. For example, the tendency to obesity. American researchers who worked with mice found that animals with a certain set of bacteria in their intestines ate more than other mice and, accordingly, got fat. When transplanting bacteria from fat rodents to thin ones, the latter developed an increased appetite, and they also increased in size. The bacteria inhabiting the digestive tract of fruit flies control the lives of their hosts even more strictly - it was recently found that they largely determine the choice of a mate for mating.

Also, bacteria determine the ability to metabolize certain medications, and, finally, sometimes they still begin to harm the host, provoking the development of diseases such as eczema and psoriasis.

ExoplanetsFor a long time, the presence of planets in other stars was just a hypothesis.

That is, astronomers understood that there are many stars in the Universe (and many of them are very similar to the Sun) and some of them probably have one or more "charms", but it was impossible to detect extrasolar planets, disproportionately smaller and dimmer compared to their stars, because of imperfections technicians.

The first reliable report of the existence of exoplanets appeared in 1992 – scientists found several planets orbiting the pulsar. In 1995, a planet was found near the star. Since then, the number of newly discovered planets has been constantly increasing, and the rate of their detection has been increasing. In 2009, the Kepler orbital telescope was launched into space, whose instruments make it possible to find not only planets, but even their satellites. Since it started working, the lists of exoplanets known to scientists have been replenished even faster – in total, by the end of 2010, astronomers had discovered more than five hundred extrasolar planets.

So far, most of them have been found by indirect methods – that is, astronomers could not observe the planet directly, but concluded about its existence by assessing the influence that the planet has on its star. In 2008, astronomers were able to photograph exoplanets for the first time, and two years later, the radiation spectrum of a planet orbiting a star in the constellation Pegasus was directly obtained. In the future, technologies for detecting and exploring exoplanets will be increasingly refined, and scientists will be able to learn a lot of new information about them, including the one that will be useful when searching for life in space.

InflammationFor a long time it was believed that inflammation is a rather complex process that occurs at the site of damage to the body or when it is attacked by pathogenic bacteria and other pathogens.

Inflammation makes it easier for immune cells to fight infection – for example, during the inflammatory process, blood vessels dilate, through which various cells reach one or another part of the body. Different stages of inflammation have been studied in detail, and scientists and doctors have developed drugs that allow controlling the intensity of this process, which sometimes acquires a pathological character (for example, with allergies).

But in recent years, researchers have suspected that inflammation is not so simple. A large amount of clinical and laboratory data indicated that inflammatory processes are the root cause of many different chronic diseases, and not only the result of infection or damage. The collected information, for example, indicates that constant inflammation is associated with the development and aggravation of Alzheimer's disease, atherosclerosis, diabetes and even obesity. On the one hand, this discovery is upsetting, since it turns out that until now doctors and scientists have misunderstood the nature of many deadly diseases. But on the other hand, now that they know in which direction to move, there is a chance that in the foreseeable future they will be able to develop new more effective approaches to the treatment of these pathologies.

MetamaterialsIn 1967, Soviet physicist Viktor Veselago suggested that some materials can refract light rays in a special way and, thanks to this feature, have very unusual properties.

At that time, there was no data on the existence of such materials, called materials with a negative refractive index, and Veselago's idea was considered nothing more than a sophisticated mind game. In 2000, several scientists developed the theory of unusual materials at once and showed that they could be created artificially – the "tricky" refraction of light would be provided not by the chemical composition of the material, but by its structure (such substances were called metamaterials).

Soon the first metamaterials were created not on paper, but in the laboratory. By forcing the rays of light to bend, such materials made the object next to them invisible to the observer – the radiation reflected from the masked object simply did not reach it. For several years, different groups of researchers have created many variants of metamaterials (although many of them still exist only in the form of calculations and formulas), "suitable" for different wavelengths. The main goal of scientists working on this topic is to create a metamaterial that would make objects invisible in the optical range, that is, not for sensors of devices, but for the human eye. However, researchers also care about other ranges – theoretically, objects can be made inaudible (or, on the contrary, inaccessible to noise) or resistant to earthquakes (seismic vibrations).

Finally, metamaterials with a negative refractive index have another use – they can be used to create (and this has already been done for some wavelengths) the so–called superlens are lenses for which there is no diffraction limit limit. That is, with the help of such lenses, you can see objects whose size is smaller than the wavelength of the radiation used.

Global warmingThis item will be the shortest.

Despite the doubts of skeptics and the "climategate" that broke out at the end of 2009, most scientists believe that global warming is a reality and that one of the reasons for this process is human activity. Scientists' confidence is explained by the fact that too much evidence confirms that our planet is getting warmer every year.

Portal "Eternal youth" http://vechnayamolodost.ru
23.12.2010