It was Johannes Krause from Leipzig, strangely excited.

Aquaculture also involves the heavy use of noisy equipment such as aerators, air and water pumps, filtration systems, etc., which degrade the acoustic conditions in fish tanks. Continuous exposure to intense noise levels can adversely affect cultivated species. One of the consequences of this impact is increased stress and reduced growth. And with artificial reproduction of fish, a decrease in the acoustic sensitivity of fry will negatively affect their survival in the natural environment in the future (Montgomery et al., 2006).

Lake Baikal is an ideal testing ground for studying sound propagation models and assessing the impact of noise on aquatic life (Glotin et al., 2017; Sapozhnikova et al., 2017). New data on the morphology of the auditory epithelium of Baikal fish allow us to assess the physiological aspects of their behavior in different zones of Lake Baikal, which differ in acoustic conditions.

The group https://123helpme.me/synthesis-essay/ of fish sensory biology of the Limnological Institute of the Siberian Branch of the Russian Academy of Sciences (Irkutsk) is currently actively studying the effect of low-frequency and high-frequency sound on the hearing of Baikal fish, analyzing the ability of hair cells to recover after intense sound stimulation. It turned out that, depending on the intensity, sound can cause mechanical damage to hair cells in whitefish, temporary or permanent hearing loss, and behavioral disturbances.

Experiments on Baikal whitefish have shown that stimulation with an intense single-tone sound leads to various damage to their auditory epithelium: on the left – the epithelium of fish reared under normal conditions, on the right – fish exposed to noise

The relevance of studying the effects of long-term exposure to noise on hearing and acoustic behavior of Baikal fish is associated, in particular, with the need to obtain forms of coregonid fish that are resistant to stress and potentially promising for aquaculture. This is due to both a decrease in the number of their populations in nature and the introduction in 2017 of a ban on catching the main commercial species of whitefish – Baikal omul. It is hoped that the results of acoustic studies of Baikal fish will eventually be used to mitigate the anthropogenic impact on them in their natural environment, and the creation of favorable conditions for rearing fish fry will help replenish the populations of endangered species.

A high experimental noise load in Baikal whitefish leads to ruptures of the auditory epithelium equal to the size of a hair cell (a), as well as to pathological changes (vacuolization) of the cells themselves (b)

Under the pressure of scientific knowledge, modern man gradually loses his mystical faith in the “sacredness” of one of the most beautiful corners of the world – Lake Baikal, which is quite natural. But this does not mean that now we should not take care of the cleanliness of the great lake and the unique representatives of its animal world, more than half of which are not found anywhere in the world. Solving the secrets of Lake Baikal, we must learn to reasonably interpret scientific facts, not forgetting that nature also speaks to us, albeit in a special language. And are we always able to hear it?

This work was supported by a project of the Russian Foundation for Basic Research and the Government of the Irkutsk Region (project No. 17-44-388081 r_a), as well as by the project of the Government of the Irkutsk Region “Obtaining high-tech aquaculture of whitefishes …” (Forum “Baikal”). Studies of the effect of intense sound on fish were carried out within the framework of the budgetary theme 0345-2016-0002 (“Molecular ecology and the evolution of living systems …”).

Ultrastructural photographs of the sensory epithelium were obtained on the basis of the Joint Center for Ultramicroanalysis of the LIN SB RAS (Irkutsk).

Literature1. Bibikov NG, Sukhoruchenko MN, Rimskaya-Korsakova LK Influence of anthropogenic sounds on the biota of the Arctic seas // Reports of the XXVII session of the Russian acoustic society. SPb., 2014, pp. 1–13.2. Kasumyan AO Structure and function of the auditory system of fish. Moscow: Moscow State University Publishing House, 2005.110 p.3. Kuznetsov Yu. A., Kuznetsov M. Yu. Substantiation and development of methods and means of commercial bioacoustics: Monograph. Vladivostok: Dalrybvtuz, 2007.339 p.4. Lychakov DV Research of otoliths of fish in connection with vestibular and auditory functions // Sensory systems. 1994. T. 8.No. 3/4. S. 7-15.5. Sapozhnikova Yu. P., Klimenkov IV, Melnik NG Features of morphological polarization of sensory elements of the auditory saccular epithelium in Baikal horned fishes (Cottoidei) // Sensory systems. 2007. T. 21. No. 2. P. 140-146.6. Sapozhnikova Yu. P., Klimenkov IV, Khanaev IV Features of the formation of otoliths in some horned fishes of different ecological groups of Lake Baikal // Sensory systems. 2010. T. 24. No. 1. P. 73–86.7. Glotin H., Poupard M., Marxer R. et al. Big data passive acoustic for Baikal lake Soundscape  Ecosystem Observatory [B2O] // Toulon: DYNI CNRS LSIS team. 2017. P. 1–25.8. Montgomery J. C., Jeffs A. G., Simpson S. D. et al. Sound as an Orientation Cue for the Pelagic Larvae of Reef Fishes and Decapod Crustaceans // Adv. Mar. Biol. 2006. V. 51. P. 143-196.9. Popper A. N., Ramcharitar J., Campana S. E. Why Otoliths? Insights from Inner Ear Physiology and Fisheries Biology // Mar. Freshwater Res. 2005. N. 56. P. 497-504.10. Sapozhnikova Yu. P., Klimenkov I. V., Khanaev I. V. et al. Ultrastructure of saccular epithelium sensory cells of four sculpin fish species (Cottoidei) of Lake Baikal in relation to their way of life // J. of Ichthyology. 2016. V. 56. N. 2. P. 289–297.11. Sapozhnikova Yu. P., Belous A. A., Makarov M. M. et al. Ultrastructural correlates of acoustic sensitivity in Baikal coregonid fishes // Fundam. Appl. Limnol. 2017. V. 189. N. 3. P. 267-278.

“Science at first hand” №5 / 6 (80), 2018

The December issue of Science published a list of the top ten scientific breakthroughs of the past year. This “top ten” also includes the results of a paleogenetic study of a bone fragment discovered in 2012 in Denisova Cave in Altai Mountains. It turned out that this fossil bone belonged to a direct descendant of representatives of two groups of ancient people – Denisovans and Neanderthals. The discovery was made public at the international symposium “Origins of the Upper Paleolithic in Eurasia and the evolution of the genus Homo”, held in July 2018 at the research station of the Institute of Archeology and Ethnography of the SB RAS, in the immediate vicinity of Denisova Cave, the site of the discovery of a unique find. Thanks to many years of cooperation with Novosibirsk archaeologists, the staff of the Science First Hand magazine were able not only to attend the symposium, but also to witness a change in the scientific paradigm in human evolutionary biology, which was largely a consequence of the study of Altai finds.

Although today many people are confident in the divine act of human creation, over the past hundred-odd years science has accumulated a lot of convincing evidence of the long and gradual evolution of our very distant ancestors, which separated from the common evolutionary stem with great apes about 6-7 million years ago. At the same time, the process of becoming a person turned out to be far from as simple and unambiguous as it seemed to the first researchers.

The new science that emerged in the 1980s was able to bring clarity to this picture. at the junction of molecular biology, classical archeology and paleontology – paleogenetics. Now scientists were able to isolate and identify DNA sequences from fossil remains, which made it possible to study extinct species and populations of organisms that have disappeared from the face of the Earth, including human ancestors.

The most weighty arguments in support of the multi-regional concept of human evolution were based on the data of long-term large-scale studies in the Russian Altai, which were once begun by Academician A.P. Okladnikov. An interdisciplinary study of the Altai Paleolithic made it possible to conclude that cultural traditions evolved for at least 300 thousand years without noticeable signs of external influences, including the formation of the Upper Paleolithic 50–40 thousand years ago. But what were the people who made the items and adornments typical of the early Upper Paleolithic period before the inhabitants of Europe?

Unfortunately, the Altai Paleolithic is stingy with anthropological finds, which, moreover, are represented by rare finds of teeth and fragmentary bone fragments, which makes it impossible to recreate the appearance of their owners. In 2005, Academician Derevianko wrote: “The wildest hopes are to find a human skeleton of the Paleolithic era in Altai. We have small paleoanthropological finds that are currently being studied at the Max Planck Institute for Evolutionary Anthropology in Leipzig – teeth, a piece of bone. But a complete skeleton is, albeit a specific, but the most cherished dream of an archaeologist. ” The complete skeleton of a fossil person in Altai has not yet been discovered, but, nevertheless, the reality has surpassed the wildest expectations (Shunkov, Derevyanko, 2018).

Not so long ago, one of the most likely candidates for the role of our ancestors was considered a Neanderthal, whose brain volume was not inferior to modern humans and was well adapted to the conditions of temperate latitudes. But as a result of the first paleogenetic studies of mitochondrial DNA from fossil bone remains, Neanderthals were recognized as a dead-end branch of humanity. They were rehabilitated only at the beginning of the new millennium thanks to the emergence of advanced DNA sequencing technologies, with the help of which it was possible to “read” nuclear DNA and prove that the genome of an average person with non-African “roots” has 1–2% of genes of Neanderthal origin.

The sensational results of studying fossil bones from Denisova Cave are reported at a symposium dedicated to the origins of the Upper Paleolithic, a member of a large international research team Vivian Slon from the Institute for Evolutionary Anthropology of the Max Planck Society (Germany). Gorny Altai, 2018

Bone anthropological remains of Neanderthals, analyzed at the Institute of Evolutionary Anthropology of the Max Planck Society (Leipzig, Germany), also included samples from the Altai caves, Denisova and Okladnikov, which are distinguished by excellent preservation due to the “cave” climate. Among them was a small bone from Denisova’s cave – a phalanx of the little finger of a child, the results of the analysis of which became a real sensation.

Professor S. Paabo from the Max Planck Institute for Evolutionary Anthropology (Germany) talks about deciphering ancient DNA from the fossil bones of a Denisovan man. Gorny Altai, 2018. Right: a fragment of a fossil bone, about 2.5 cm long, found in the eastern gallery of the Denisova Cave. The age of the bone, according to radiocarbon dating, is more than 50 thousand years. Photo by T. Khayyam

The director of the laboratory of evolutionary genetics S. Paabo wrote about this discovery:

“In the spring of 2009, we received another bone fragment from Anatoly [Derevianko], which was found the previous year in Denisova cave … The bone was tiny, and I did not attach much importance to it, deciding only when there would be time to analyze it about mtDNA content … On December 3, 2009, I attended the rat genome meeting. One day, as I was heading from the cafeteria to the lecture hall, my cell phone rang. It was Johannes Krause from Leipzig, strangely excited. I asked him what happened. He, in turn, asked if I was sitting, and said that I had better sit down before I hear the news … “.

This amazing news was the discovery of a new, unknown to science species of man, which literally turned upside down the ideas of the origin and evolution of Homo sapiens that had been established by that time.

At the beginning of July 2018, the leading archaeologists, geneticists, paleontologists and anthropologists from Russia, USA, Germany, Great Britain, France, Croatia, Israel, Canada and Australia gathered at the Denisova Cave station of the Institute of Archeology and Ethnography of the SB RAS (Novosibirsk)

Paleogenetic analysis of the fossil bones of the Denisovan man showed that he, like the Neanderthal man, left his “mark” in the genome of many modern human populations. And judging by the genetic diversity, in the Stone Age it was the Denisovans who constituted the main population of North Asia.

Findings of bone remains in the same cultural layers of the Denisova Cave indicate that the Denisovans and Neanderthals lived in this area at the same time. But what was their relationship like? It is difficult to answer this question unequivocally, but the latest find clarified a lot.

Left: Professor S. Paabo Director of the Evolutionary Genetics Laboratory of the Max Planck Institute for Evolutionary Anthropology (Germany). Right: Corresponding Member. RAS M. V. Shunkov, Director of the Institute of Archeology and Ethnography SB RAS and head of the largest archaeological research station in Russia “Denisova Cave”

Denisova-11 is a small bone for which it was not even possible to establish its exact location in the skeleton. By comparing it with the well-known long bones of Neanderthals and modern humans, it was possible to determine that it belonged to an individual not younger than 13 years old. After sequencing the nuclear DNA extracted from the sample, the scientists found that it was a young girl, whose genome contained about 42% of Denisovan genes and 39% of Neanderthal genes. In other words, among her ancestors she had representatives of two ancient groups, and in equal proportions. Judging by the degree of heterozygosity (nucleotide differences) of the genome, it had two different sets of parental chromosomes: one from the Denisovan, and the other from the Neanderthal. And given the mitochondrial DNA, which is always inherited through the maternal line, it can be argued that the Denisovan was her father, and the Neanderthal was her mother.

Professor M. Volpoff from the University of Michigan (USA), one of the first supporters of the hypothesis of the polycentric origin of man, is speaking. Gorny Altai, 2018

Academician A.P. Derevyanko:

“The latest discovery in Denisova Cave is extremely important, as it proves once again that there was a constant exchange of genes between the ancient populations of people formed in different territories. And he could only go between different subspecies, since crossing between different species does not give fertile offspring. Thus, this discovery confirms the hypothesis that several different subspecies of Homo sapiens were directly involved in the formation of modern humanity. “

Before the report: scientific supervisor (from 1983 to 2015 – director) of the Institute of Archeology and Ethnography of the SB RAS, Academician of the RAS A.P. Derevyanko with the head of the excavations in Denisova Cave, Ph.D. n. M. B. Kozlikin. Gorny Altai, 2018

Moreover, studies have shown that the Denisovan Pope himself, many generations ago, also had at least one Neanderthal ancestor in the family. And my mother turned out to be genetically closer to the Neanderthals from the Croatian cave Vindia, and not to her Altai “neighbors”, that is, she could belong to a group of relatively recent settlers from Eastern Europe.