This can not live : The most amazing hypotheses from the field of biology

(ORDO NEWS) — Fantastic ideas in science are most often expected from physicists, because they study what is happening on the largest and smallest scales of reality.

Indeed, quite a few unexpected hypotheses are put forward, for example, in cosmology and quantum mechanics.

But even on a biological, human scale, there are quite audacious versions and assumptions. Here are just a few of them.

Life from Mars

Any comparison of Earth and Mars in terms of fitness for life today will not be in favor of the Red Planet.

But this was not always the case: Mars formed before the Earth, in addition, our planet almost immediately experienced a powerful collision with a celestial body, the fragments of which formed the Moon.

While the Earth was recovering from the impact, its neighbor was a much more comfortable place.

A couple of years ago, American scientists led by Benton Clark conducted a detailed review of scientific publications on this topic and concluded that life could have originated on Mars with no less probability than here on Earth – and possibly even more.

In fact, it is possible to obtain a mixture of simple organic substances without the participation of living beings – this was shown at the end of the last century.

However, it is still unclear how complex RNA molecules were formed from them, capable of transmitting hereditary information and catalyzing chemical reactions, changing and evolving, that is, the precursors of a full life.

To begin with, free RNA easily decomposes in an aqueous solution, and the Earth, which had cooled down after the impact and the formation of the Moon, was completely covered by the ocean.

The most massive of the Martian meteorites found on Earth weighs almost 15 kg.

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But on Mars, even then, periods of humidity and drying alternated, during which places could appear where RNA remained stable.

In addition, during the evaporation of moisture in water bodies, phosphorus, which is necessary for the appearance of new RNA molecules, boron and manganese, which are useful for their stabilization in water, sulfur, and other microelements, could be concentrated.

In the earth’s crust, they are rarer or are in a hard-to-reach form, such as, for example, inert apatites, in which most of the phosphorus in the earth’s crust is accumulated.

By the time Mars lost its atmosphere and moisture and became unfavorable for life, its “embryos” could well have migrated to Earth.

In general, the exchange of material between neighboring planets is quite intensive: to date, scientists have discovered more than 300 meteorites of Martian origin.

It is believed that at least 500 relatively large fragments knocked out from the surface of Mars fall on our planet every year.

Once upon a time, on such a piece of stone, proto-life could also migrate, replacing its native, but dying planet with a neighboring one.

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Organisms from the tumor

Cancer is a terrible disease, but it is not dangerous for others. Only a few cases are known when it became contagious.

Thus, a transmissible facial tumor mows down entire populations of marsupial Tasmanian devils. The disease has been spreading since the early 1990s, originating from a single individual in whose nervous tissue it originated.

The cells of this tumor have lost most of the genome, including many specific markers, and have gained the ability to be transmitted from devil to devil by contact, like a completely independent parasite organism.

The idea that the cells of complex animals that have survived a malignant transformation can be considered as separate organisms and even the beginnings of new species appeared at least in the middle of the 20th century.

This hypothesis is still considered marginal and poorly compatible with modern views on speciation, and yet scientists return to it every now and then.

Not so long ago, Alexey Panchin, together with colleagues from the Moscow Institute for Information Transmission Problems, examined a whole group of rather unusual sea creatures.

We are talking about parasitic myxosporidium – primitive cnidarians, relatives of jellyfish and coral polyps, consisting of a maximum of several dozen cells. Their genome is extremely simple, unusual even for parasites.

Moreover, it lacks entire blocks responsible for the interaction of cells within a single organism. According to Panchin and his co-authors, myxosporidium could have originated from the transmissible crayfish of ancient cnidarians.

Transmitted from one individual to another, the tumor managed to survive even after the death of the first carrier.

Subsequently, one of her clones could mutate, gaining the ability to spread between representatives of different species.

And finally the tumor again received multicellularity, albeit limited. The first step in this chain looks the most realistic.

Similar examples are known not only from the life of the Tasmanian devils – for example, the transmissible venereal tumor of dogs has been transmitted between canids for several thousand years.

It is extremely rare, but interspecies infection also occurs: a case of cancer transmission from a parasitic worm to an HIV patient is known.

It is more difficult to imagine how the cancer cell returned to an almost normal state.

No matter how simple myxosporidium may be, they still contain cells of different types and specializations, which seems to be an unattainable complexity for a tumor.

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At different stages of their life cycle, myxosporidium can parasitize fish or marine worms

Consciousness from viruses

Unlike bacteria, viruses are parasites that work directly with the genome. Some of them can even insert their own DNA into the host’s chromosomes. Such fragments are able to hide in cells for a long time, passing from generation to generation.

Inside the body, they often experience new mutations, gradually losing activity; about 40% (and according to some estimates, up to 80%) of the human genome are such remains of ancient viruses that have accumulated over millions of years of evolution of our species.

The proteins encoded by the ARC gene fold into hollow shells that look suspiciously like virus particles.

Over time, these viral DNA fragments can acquire new useful functions. It is believed that they play an important role in embryonic development and the functioning of the immune system. It is possible that former viruses also ensure the functioning of the complex nervous system of animals.

The best-known example of such an application is the ARC gene, which is involved in the mechanisms of synaptic plasticity.

Through synapses – special contacts – there is an exchange of signals between neurons, which transmit small neurotransmitter molecules to each other. The ARC gene is activated when glutamate receptors are activated in the synapses.

Proteins produced from this gene immediately form “bubbles”, collecting small RNA molecules into themselves and turning into a kind of virus. They really are transmitted to neighboring cells, “infect” them and again release the accumulated RNA.

Recently, the ARC gene was shown to be derived from the Ty3/gypsy retrotransposon, an ancient genetic element related to retroviruses. Moreover, it seems that the virus – the ancestor of ARC was integrated into the genome of animals more than once.

This gene in tetrapods – four-legged vertebrates – differs from its counterpart, which is carried in their chromosomes by insects. Perhaps they got their ARC independently of our ancestors.

However, it seems that the mechanism of its action is generally the same in us and in fruit flies: “ARC viruses” collect RNA and “infect” neighboring neurons with them.

What exactly the RNA molecules delivered to the cell do is unclear. However, experiments with cell cultures have shown that without them, synapses quickly lose stability, and the connection between neighboring neurons disappears.

As a result, neither learning, nor memorization, nor the performance of complex cognitive functions.

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Love for immunity

Among the main tasks of immunity, one can name not only the fight against foreign agents, but also the destruction of one’s own cells that have worked out their own or survived malignant degeneration.

The separation of normal cells from damaged ones occurs with the help of proteins of the major histocompatibility complex (MCHC), which are recognized by lymphocytes.

This is a very ancient mechanism, dating back to the first jawed fish, but it retains a huge influence on modern people.

In the 1990s, the “sweaty T-shirt experiment” was conducted, in which courageous female volunteers were asked to smell and evaluate things after a couple of days of men wearing them.

As a result of blind tests, it turned out that ladies invariably preferred the smells of men whose MHC proteins did not match their own as much as possible.

These experiments have been criticized more than once by experts, but there is other evidence that partners seem more attractive to us, an alliance with which promises advantages to offspring.

The similarity of MHC proteins may indicate the genetic proximity of a man and a woman and often leads to difficulties in conception.

The Swiss startup GenePartner, despite the unproven hypothesis, even promises to match a couple based on DNA analysis. But the effect of falling in love on immunity has already been demonstrated quite clearly.

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