Which animal is closest to man. It's still unrealistic to clone a Neanderthal ... Human and Pig Relatives

The progenitor of domestic pigs is the wild boar, belonging to the genus of artiodactyl non-ruminants. Currently, these farm animals are bred in many countries around the world. But they are most popular in Europe, Russia and the states of East Asia.

Pig appearance

Domestic pigs do not differ too much from their ancestors, wild boars. The only thing is that piglets are usually not covered with such thick hair. The anatomy of a pig and a wild boar is also almost identical.

Distinctive features of domestic piglets are:

• compact physique;
• feet with hooves;
• hairline represented by bristles.

The elongated muzzle, ending with a heel, which serves in the search for food to loosen the soil, is, of course, also one of the main characteristic features of a pig. In the photo below you can see how convenient it is for piglets to use this organ, even when kept at home. It is a piglet of a pig cartilaginous movable disc.

By the shape of the pig's head, you can, among other things, determine its appearance. In representatives of meat breeds, it is somewhat elongated. In greasy piglets, this part of the body is more rounded.

Pig Anatomy: Musculoskeletal System

Piglets belong to the class of mammals. The skeleton of these animals is represented by about 200 bones. At the same time, the following varieties are distinguished:

• long tubular;
• short;
• long, curved;
• lamellar.

The pig skeleton itself consists of several sections:

• skull;
• torso and tail;
• limbs.

The muscular system of the pig is represented by smooth muscles and skeletal muscles. The bones in the body of these animals connect the forming joints. In total, pigs have several unpaired and about 200-250 paired muscles.

Digestive and excretory system

Piglets are almost omnivorous animals. And the digestive system in pigs is, of course, very well developed. Its main departments are:

• oral cavity;
• pharynx and esophagus;
• unicameral stomach;
• large and small intestines;
• rectum;
• anus.

The liver is responsible for filtering blood and neutralizing harmful substances in pigs, as in any other mammals. The stomach in these animals is located in the left hypochondrium, and the pancreas in the right.

Genitourinary system

One of the undoubted advantages of pigs as farm animals is their high fertility. The reproductive system of boars is represented by the following organs:

• scrotum and testis;
• duct and spermatic cord;
• the urogenital canal;
• penis;
• a special skin fold covering the penis - prepuce.

The reproductive system of a female pig is represented by the following organs:

• ovaries;
• fallopian tubes;
• uterus and vagina;
• external organs.

A pig's sexual cycle can last from 18 to 21 days. These animals bear cubs for 110-118 days. One sow can give birth to up to 20 cubs. This is even more than that of the rabbits famous for their fertility.

The urogenital system of the pig is also represented:

• paired kidneys;
• ureters;
• bladder;
• the urethra.

In males, the urethra conducts, among other things, reproductive products. In pigs, it opens on the eve of the vagina.

Nervous system

Pigs are highly developed animals. It is believed that in intelligence they are close to dogs. These animals, for example, can be easily taught to carry out all sorts of commands. Like dogs, pigs are able to return from afar to the places where they once lived.

The nervous system of these animals is represented by:

• the brain and spinal cord with ganglia;
• nerves.

The brain of these animals has two hemispheres with convolutions and is covered with cortex. Its mass in pigs ranges from 95-145 g. The length of the spinal cord in these animals can be equal to 119-139 cm.

The cardiovascular system

Like other mammals, the heart is the central circulatory organ of pigs. It has a conical shape and is divided by a longitudinal partition into right and left halves. By rhythmically contracting, the pig's heart drives blood throughout its body. Each half of the animal's heart, in turn, is divided by transverse valves into the ventricle and atrium.

Pig blood consists of plasma and erythrocytes, platelets and leukocytes floating in it. From the heart through the body of animals, it flows through the arteries, and returns to it through the veins. Also, the pig's circulatory system is represented by capillaries through the walls of which oxygen enters the tissues.

All kinds of foreign particles and microorganisms are neutralized in the body of these animals in the lymph nodes.

Features of the structure of the skin of pigs

Piglet skin thickness can vary between 1.5-3 mm. In purebred pigs, this indicator may even be equal to only 0.6-1 mm. At the same time, the subcutaneous layer of piglets contains a very large amount of fat and can reach enormous thickness.

Sexually mature males have a shield on the sides of the shoulder girdle and chest, consisting of compacted bundles with fat pads. This formation protects the wild boars during fights during the sexual hunt.

Coarse hairs of bristles on the skin of pigs alternate with soft ones. The hair density of piglets of different breeds may not be the same. In most cases, farms, of course, breed naked pigs. But there are also breeds whose representatives are covered with thick wool, about the same as wild boars.

Analyzers, hearing and vision organs

The pig's cardiovascular system is thus very well developed. The same goes for the other organs of the piglets. For example, pigs have excellent sense of smell.

The organ responsible for the perception of odors in these animals is located in the nasal passage and consists of:

• olfactory epithelium;
• receptor cells;
• nerve endings.

Touching in pigs is carried out by receptors of the musculoskeletal system, mucous membranes and skin. The organs of taste in these animals are the papillae located in the oral mucosa. The eyeballs in pigs are connected to the brain by the optic nerve.

The ears of these animals are composed of the following sections:

• cochlear part;
• conductive paths;
• brain centers.

Similarities and differences between pigs and humans

People, as everyone knows, belong to the class of primates and descended from the monkey. Outwardly, a person, of course, most of all resembles this particular animal. The same applies to the structure of the internal organs. However, in terms of physiology and anatomy, a person is also quite close to a pig.

For example, like humans, piglets are omnivorous animals. It is believed that they were once tamed precisely because of this. Wild boars willingly ate the remains of human food. The only difference between humans and pigs in this regard is that the latter have fewer bitter taste receptors in their mouths. Piggy perceives sweet and bitter things in a slightly different way than humans.

As you know, the structure of the pig's heart is not much different from the human heart. Doctors even try to use piglets in this regard as donors for both humans and monkeys. The heart of piglets weighs 320 g, in humans - 300 g.

Very similar to human and pig skin. These animals, like humans, can even sunbathe. They are also similar in structure in humans and pigs:

• eyes;
• liver;
• kidneys;
• teeth.

The yellow press sometimes even flashes information that sometimes sows in the United States and China are used to carry human embryos.

What Scientists Think

People have been raising piglets for a long time. And the anatomy of pigs is studied, of course, just fine. Unfortunately, there is no definite answer to the question of why piglets and primates are so similar. In this regard, there are only a few unverified hypotheses. For example, some scientists believe that the pig itself was once descended from a primate.

There is even confirmation of this incredible hypothesis. On the island of Madagascar, researchers have found the fossil remains of lemurs with a long snout with a snout. Like pigs, these animals once ripped open the ground with their noses in search of food. At the same time, instead of hooves, they had a five-fingered hand, like a man's. Yes, and in the embryos of modern pigs, oddly enough, there is a bud of a five-fingered hand and a muzzle, like a primate.

Ancient legends are also a kind of confirmation that piglets were once primates. For example, in one of the legends of the inhabitants of the island of Bot, it is stated that in ancient times the hero Kat made people and pigs according to the same model. However, later the pigs wanted to have their own differences and began to walk on four legs.

Diseases of humans and pigs

Scientists have noticed that the similarities between humans and pigs are not limited to the anatomical structure of organs. Almost the same diseases in primates and pigs. For example, pigs, like humans, can be diagnosed with Alzheimer's disease in old age. Also, piglets are very often obese. Parkinson's disease can also be observed in these animals. The pig in the photo below suffers from just such a disease.

Transgenic animals

The heart and other organs of piglets and humans are similar. But still they are not identical. Experiments on the transplantation of pork organs to humans have ended so far, unfortunately, with failures due to tissue rejection. To solve this problem, scientists began to breed special transgenic pigs. In order to get such piglets, two human genes are introduced into the embryo and one pig is turned off.

Many scientists believe that future breeding experiments in transgenic pigs may actually help solve the problem of tissue rejection in organ transplants. By the way, there is already evidence of this. For example, in 2011, Russian surgeons successfully transplanted a transgenic pig heart valve into a patient.

Genetic similarity

The anatomy and physiology of pigs is such that, according to some scientists, they are an accurate biological model of humans. In terms of DNA structure, monkeys are, of course, closest to humans. For example, the difference in genes between humans and chimpanzees is only 1-2%.

But pigs are also close enough to humans in terms of DNA structure. The similarity between human and pig DNA is, of course, not that great. However, scientists have found that in humans and piglets, some types of proteins are very similar in composition. That is why piglets were once actively used to obtain insulin.

Recently, such a topic as the cultivation of human organs inside piglets has caused a lot of controversy in the scientific world. Purely theoretically, carrying out such procedures is nothing impossible. After all, the genomes of humans and pigs are indeed somewhat similar.

To obtain organs, human stem cells can simply be placed in a sow's egg. As a result, a hybrid will develop, from which not a full-fledged organism will grow, but only one organ. This can be, for example, the heart or the spleen.

Of course, organs grown inside pigs could save the lives of many people. However, many scientists are opposed to this method. Firstly, conducting such experiments, of course, is inhumane in relation to the pigs themselves. Secondly, it is believed that the cultivation of organs for humans in pigs could lead to the emergence of new genetically modified pathogens that can claim the lives of millions of people.

Pig man genome

Pig blood is biologically 70% similar to human blood. This made it possible to carry out one very interesting experiment. Scientists took a pregnant sow and injected embryos with white human blood containing hereditary information. The animal's pregnancy ended in successful childbirth.

In the blood of the piglets born, the researchers subsequently found cells containing large sections of both human and porcine chromosomes. This, of course, became a real sensation in the scientific world. Among other things, such cells in the piglets' bodies were also resistant. That is, they persisted for a long time after birth. Simply put, scientists were the first to obtain a stable human-pig genome. Of course, there were few such cells in the bodies of the tested pigs and the animals were in no way similar to humans. However, the resulting genome contained more than a third of human material.

Other research scientists

Be that as it may, the anatomy of pigs is well studied, and the idea of ​​using these animals as donors looks quite attractive. At the same time, most scientists believe that nothing is impossible in this. Researchers already have quite serious achievements in this regard. For example, scientists managed to find out that nerve cells taken from the body of piglets are able to put paralyzed people on their feet.

High-quality contact lenses are already being made from pork collagen. The piglet ear cartilage cells are used to grow artificial breasts. Also, scientists have created a pig that produces omega-3 fatty acids that are useful for the human heart.

- What discoveries, achievements in the field of human evolutionary genetics do you consider the most important over the past 10 years? 20 years? 50 years?

In the evolutionary genetics of both humans and other species, the most important results were provided by DNA analysis - it made significant changes in the concept of the evolutionary tree. For humans, this analysis proved that all modern humans descend from a single ancestral group that lived in Africa.

Important: the migration routes drawn on the basis of DNA analysis of modern populations do not pass through mountains and rivers, but through populations (which now live there, and their ancestors could have lived in another place). To link migration paths to geographic features, data on ancient DNA is needed.

In different sources, you can see different numbers characterizing the closeness of the human and chimpanzee genomes - 98.5% or, for example, 94%. What determines this spread of numbers, and yet, what is more correct?

The spread of the numbers depends on what type of distinction between genomes is used. Nucleotide "texts" can differ by substitutions of individual letters (the so-called single nucleotide polymorphisms ", the English abbreviation SNP, Single Nusleotide Polymorphism), the number of repeated fragments (CNV, Copy Number Variation), the arrangement or orientation of large fragments can be changed (these changes have long been known as changes in the position of chromosome fragments).

Genomes can differ in the presence of insertions or the loss of fragments of different sizes. In addition, two monkey chromosomes in humans are combined into one, so we have 46 chromosomes, and chimpanzees have 48.

It is difficult to indicate in one figure all these various restructuring, therefore, depending on what was taken into account, the numbers turn out to be different. But when any type of difference is taken into account, the picture of similarity between species is the same - chimpanzees are closest to humans, then gorilla, then orangutan, and so on.

These few percent that distinguish the human genome from the chimpanzee genome - what is their "physical meaning"? What are these genes, what are their functions?

When comparing the genomes of humans and chimpanzees, mutations were identified that "made us human." These are the mutations that appeared in the human line and led to important changes in biochemical processes, body shape, or changed the maturation of certain systems.

However, this "physical meaning" has very few differences. Basically, the differences are due to the random accumulation of "neutral" mutations that do not manifest themselves in any way in the appearance or biochemical characteristics of their owners.

Some of the "semantic" differences are associated with the accumulation of adaptive mutations, with one mutation in the chimpanzee genome and others in the human genome. Among the known changes are mutations that inactivate some genes "unnecessary" for humans. For example, the inactivation of the gene for keratin, a protein that is part of the hair, is associated with the absence of hair on the human body. Inactivation of genes for olfactory receptors in humans is associated with a decrease in the role of smell for survival. An important change is the inactivation of the gene of one of the proteins that is part of the masticatory muscles. The weakening of the powerful chewing muscles attached to the bones of the skull made it possible to "free" it from the functions of the skeleton for these muscles and to increase the size of the cranium, and, accordingly, the size of the brain.

Mutations in genes associated with brain size and function are particularly interesting. In human ancestors, mutations in genes that control brain size accumulated, and those that led to an increase in brain size were selected.

An important class of mutations that distinguish humans from other primates is changes in the genes of regulatory proteins. These proteins regulate the work of entire groups of other genes, and a change in one such protein leads to significant changes in the work of gene ensembles. By changing these proteins, due to a small number of mutations, significant changes in the structure and functions of various organs can be achieved.

The differences between the genomes of humans and primates have already been "inventoried", but the meaning of these differences is still clear only for a small fraction of mutations.

How do you feel about the suggestions of some researchers based on genetic data to include chimpanzees and gorillas in the genus Homo?

Positively. Formally, at the DNA level, the primate brothers and I differ less than the two species of rats. Although in appearance and lifestyle we differ much more.

Probably a naive question, but will it be possible in the foreseeable future by means of genetic engineering to "make a man out of a monkey"? What difficulties stand in the way of solving such a problem?

What for? we already are - nature has already done. I believe that it is unethical to make a factory for the production of something from half-people, half-monkeys (it is possible to obtain various useful substances from microorganisms or from tissue cultures), and philosophical problems cannot be solved in this way. It is better to preserve the natural populations of our relatives.

Another science fiction question: is it possible in the foreseeable future to solve such a problem as cloning a Neanderthal?

Cloning from the available DNA fragments is impossible - they are very short, you cannot sew them into a single whole. DNA synthesis based on the information obtained about the sequence of the Neanderalian genome is still hardly possible. When determining the nucleotide sequence of ancient DNA, there is a high probability of an erroneous "reading" due to the fact that over thousands of years, chemical modifications accumulate in DNA that can be mistaken for real mutations. In addition, DNA is synthesized in a test tube in fragments of several thousand nucleotides. When assembling these fragments, errors also occur. As a result, the number of errors will be so great that the system will not be viable. But there is still the stage of introducing DNA into the cell. And some more technical difficulties - for example, how to make the level of DNA methylation.

DNA methylation is a method of chemical modification of certain nucleotides (hanging a methyl group with special enzymes). Methylation can affect the activity of genes, the recognition of DNA by enzymes (for example, restriction enzymes, which, depending on the presence or absence of a methyl group, cut or do not cut certain sequences), and more.

You can read more about the problems associated with the study of ancient DNA in this article.

Unfortunately, the Russian Internet is full of all sorts of misinformation (for example, we regularly come across rantings that genetically it is not a chimpanzee but a pig that is closest to humans ...). What are the most common myths and misconceptions about human genetics?

There is a well-known myth about pigs. Insulin used to be obtained from pigs, since some of the proteins we have with pigs are really similar. And other proteins are more similar to other species of animals. Most of the coincidences - I repeat - with chimpanzees. But about the pig is better known - so old information circulates.

The most common misconceptions are associated with complete illiteracy, with the fact that many are not even familiar with the compulsory school course in genetics.

Here's an example - a response to our lecture on inheritance of blood groups. If an illiterate dad had read a page of a school textbook about dominant and recessive signs, there would be no tragedy in life:

"The material is not only interesting, but also understandable even for a junior schoolchild. I have been interested in this topic since my father (who, like my mother's Rh positive, and unfortunately I got negative) said me that because of this I am not his daughter, accused my mother of all mortal sins and left us. So, dear dad, you are deeply mistaken. You are wrong !!! "(From the site http: // www. bio.fizteh.ru/student/files/biology/biolections/lection03.html)

Scientists have proven that pigs are much closer to us than monkeys. Some pig organs can be transplanted into humans. Why so, and not vice versa?

Whether we like it or not, we all got a lot in common with pigs. We are omnivorous mammals that gain weight easily and are susceptible to influenza. The very fact that pigs and humans are mammals means that we share some genes, which is how the DNA of humans and pigs is similar.

Scientists refer to the results of studies according to which the DNA of pigs and humans are 98 percent similar, but in this state of affairs, many are misled into believing that a person is 98% a pig. The amount of genetic material we share with other species depends on what you are comparing.

All living organisms have genetic information encoded in deoxyribonucleic acid (DNA), split into pieces called genes. Information is transmitted from genes using a chemical called ribonucleic acid (RNA). Some RNA is translated into chains of amino acids that make up proteins - the building blocks of every living cell.
Scientists have discovered about 20,000 mammalian genes that code for proteins with similar basic functions. So if you compare some of the coding proteins in our DNA, you will find that we have a lot in common with a large number of mammals.

Pedigree of mammals based on molecular genetic data. It can be seen that the pig is farther from the person than the mouse, rabbit and porcupine.

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