STUDY OF GENETIC MARKERS IN THE REALIZATION OF THE SPEED OF HUMAN RESPONSE TO VISUAL STIRITUTES

Smirnova Anastasia

class 10 "M", MAOU OC Gornostay, RF, Novosibirsk

Voronina Elena Nikolaevna

scientific supervisor, Ph.D. biol. Sciences, Junior Researcher LF IHBFM SORAN, RF, Novosibirsk

Ilyina Maria Vladimirovna

scientific supervisor, biology teacher, MAOU OC Gornostay, Russian Federation, Novosibirsk

The article is devoted to the study of human reaction speed and the genes that influence it. A study was conducted on the presence of the MSTN and ACTN3 genes, and their effect on the speed of human reaction when using visual stimuli was studied. Based on the study undertaken, it was concluded that the reaction rate does not depend on the genotypes of the MSTN and ACTN3 genes.

1. Introduction

Reaction speed is one of the main qualities of any living organism. At the same time, it is very important that the response to external irritating factors is immediate, since among them there can be not just dangerous, but even fatal ones. In humans, the average reaction time to a visual signal is 0.1-0.3 seconds.

The speed of a person’s reaction is determined by the functioning of the nervous system. When a person reacts to a very strong irritation that is life-threatening, for example, when he withdraws his hand from a hot stove, a simple reflex is carried out in which the brain is not involved. From the receptor, the signal travels along the nerve fiber to the spinal cord and then directly to the muscle, passing through only three nerve cells - the sensory neuron, the interneuron in spinal cord and motor neuron. Speed nerve impulse by shoots nerve cells here - several tens of meters/sec. The determining factor is the time of synaptic transmission - about 0.1 sec. It should be noted that we first withdraw our hand and then feel pain. This is due to the fact that the signal from pain receptors to the brain travels through nerve fibers of a different type (there are three types of nerve fibers, differing in the mechanism of impulse transmission) at a lower speed of 0.5-2 meters/sec.

If we're talking about about a person’s reaction to a brick flying at him, then here is also a reflex reaction: the eye transmits a signal about rapid movement not only to the parts of the brain where they are processed (and we understand: “a brick is flying”), but also along special nerve pathways - to muscles, which provides a quick avoidance reaction, such as jumping away.

Speed ​​reaction.

Thus, the implementation of the visual signal for muscle movement occurs through the following stages:

1. the occurrence of excitation in the receptor (visual, auditory, tactile, etc.) involved in the perception of the signal;

2. transmission of excitation to the central nervous system;

3. transfer of signal information along nerve pathways, its analysis and formation of a response signal;

4. conducting a response signal from the central nervous system to the muscle;

5. muscle excitation.

What affects the speed of the reaction?

The speed and speed of movements depends on:

1. the state of the central nervous system and the human neuromuscular system;

2. Features muscle tissue(depending on the ratio of fast and slow fibers);

3. muscle strength;

4. the ability of muscles to quickly move from a tense state to a relaxed one;

5. energy reserves in the muscle (adenosine triphosphoric acid - ATP and creatine phosphate - CTP);

6. degree of mobility in joints;

7. coordination of movements during high-speed work;

8. age and gender;

9. the speed at which the brain receives a signal from the receptor and transmits it to the muscles

Genetic studies (twin method, comparison of speed capabilities of parents and children, long-term observations of changes in speed indicators in the same children) indicate that motor abilities significantly depend on genotype factors. According to scientific research, the speed of a simple reaction is approximately 60-88% determined by heredity.

Target:

Search for genetic markers of human reaction speed to visual stimuli

Tasks:

Mastering testing methods and genetic research techniques

Reaction speed testing.

Collection of samples for DNA extraction.

DNA extraction

Determination of polymorphic gene variants.

2. Progress

2.1 Testing reaction speed.

We tested 56 people on the website http://www.humanbenchmark.com/tests/reactiontime to determine the speed of their reaction to visual stimuli. The essence of the program is that a person must press the mouse button at the moment the screen color changes. For each person tested, 5 measurements were taken and the average reaction time was recorded. All measurements were carried out in the morning (everyone was under equal conditions). As a result, 16 people from 8th grade, 17 people from 9th grade, and 23 people from 10th grade were examined.

The largest number of people had a reaction speed around 265 ms (Fig. 1).

Figure 1. Reaction speed of the examined participants. The blue dots indicate the values ​​expected when normal distribution(R<0,001)

In 8th grade, the average reaction speed is 338 ms, in 9th grade - 276 ms, in 10th grade - 232 ms.

Figure 2. Dependence of reaction speed on training class

From Figure 2 we see that as the class increases, the reaction speed increases (less time is spent on the response, the person reacts faster). When statistically processing the results, it was found that the probability that the results are random is less than 0.1% (p<0,001). Следовательно, выявленная нами зависимость увеличения скорости реакции тестируемых людей с возрастанием класса не случайно, а закономерно.

Figure 3. Statistical assessment of the dependence of reaction speed on training class

2.2 Collection of samples for DNA extraction.

All students who completed the reaction speed test had their buccal epithelium collected using cotton swabs. They were then placed in 1.5 ml tubes containing 250 µl of Lysis Solution A1 and vortexed. The tubes were heated for 5 minutes at a temperature of 65 °C and mixed again using a vortex until the material was completely dissolved. Then the rods were removed, and 20 μl of sorbent resuspended by vortex was added. The contents of the tube were mixed by vortex and left in the rack for 2 minutes to sediment the sorbent. The suspension was mixed again and stood for 7-9 minutes. Next, the sorbent was precipitated in a microcentrifuge for 30 s, the supernatant was collected, 400 μl of washing solution a2 was added to each tube, and mixed by vortex until the sorbent was completely resuspended. Then it was precipitated on a Microspin for 30 s and the supernatant was collected. The washing procedure with solution a2 was repeated again, and the supernatant was carefully selected. In a similar way, the sediment was washed with 70% ethyl alcohol once, the supernatant was carefully selected, and the sorbent sediment was dried with the lids of the test tubes open in a thermostat at 56 °C. Next, 100 μl of elution buffer a3 was added, the sorbent was carefully resuspended, and placed in a thermostat at 56˚C for 10 minutes. The suspension was sedimented in a microcentrifuge at 13,000 rpm for 2 minutes. The supernatant contains purified DNA, the sample is ready for PCR.

2.3 Determination of polymorphic gene variants.

DNA samples of 5 μl were placed in 0.2 ml tubes. A mixture of primers was added to the DNA to determine nucleotide substitutions in the ACTN and MSTN genes. Next, Taq-DNA polymerase, nucleotides, and polymerase buffer were added to the tubes, and the mixture was placed in a cycler for PCR. The principle of determining a nucleotide substitution consists of repeated copying of a DNA section containing a nucleotide substitution and the interaction of this section with labeled probes. One of the probes is complementary to a nucleotide sequence with a “normal” letter, and the other is complementary to a “mutant” one. As a result, on the graph we see the glow of one of the probes if a person has only one letter (homozygote) or both probes in the case of a heterozygote (Fig. 4).

Figure 4. Graph of fluorescence accumulation by genotype G / A gene MSTN

Thus, we typed all collected DNA samples (Fig. 5).

Figure 5. Fluorescence accumulation graphs for all studied samples (a. ACTN , b. MSTN )

Unfortunately, not all samples could be typed. The genotyping results are shown in Table 1.

Table 1.

Research results for collected samples

The MSTN gene encodes the protein myostatin (also known as growth and differentiation factor 8), a protein that inhibits the growth and differentiation of muscle tissue. Animal studies show that blocking the action of myostatin results in a significant increase in lean muscle mass with virtually no fat tissue. The studied nucleotide substitution G->A leads to the premature appearance of a stop codon at position 313 of the protein and thus reduces the amount of myostatin, which leads to an increase in muscle mass and improves speed performance.

The ACTN3 gene is characteristic of type 2 (fast twitch) muscle fibers of skeletal muscles. The ACTN3 gene contains a polymorphism, R577X, which results in the replacement of arginine (C allele) at position 577 with a stop codon (T allele). The presence of this mutation results in muscles that do not contain the a-actinin-3 protein. However, muscle pathology is not observed in such people, since a-actinin-2 compensates for its absence in the Z-discs of muscle fibers. At the same time, the presence of the 577R allele, indicating the presence of the a-actinin-3 protein in skeletal muscles, gives individuals an advantage in the manifestation of speed-strength physical qualities.

In our study, no statistically significant dependence of the reaction rate on genotypes was revealed (Fig. 6) - for the ACTN gene, the level of agreement between the results in different groups was 97%, for MSTN - 80%.

Figure 6. Dependence of the reaction rate on genotypes (a. ACTN , b. MSTN )

This may be due to the fact that some of the samples were not genotyped. It is also possible that the implementation of the speed of a person's reaction to visual stimuli depends on other genes.

3. Results

· DNA samples were collected.

· The reaction speed of the test subjects was determined.

· We have shown that reaction speed increases (less time is spent responding) with increasing class.

· The genotypes of the ACTN and MSTN genes were determined for some of the tested subjects.

· No statistically significant dependence of the reaction rate on genotypes was found.

4. Conclusion

We studied genetic markers of the speed of human reaction to visual stimuli. It was found that the reaction speed increases (reaction time decreases) with increasing class and does not depend on the genotypes of the ACTN and MSTN genes.

Future plans

Complete the determination of genotypes for all samples for the ACTN and MSTN genes. Conduct research on other genetic markers (affecting the speed of nerve signal transmission).

Bibliography:

1.Sapin M.R., Nikityuk D.B. Human anatomy. In 3 volumes. M. 1998. T. 3.

2. Human physiology / Ed. R. Schmidt and G. Tevs. M.: Mir, 1996, vol. 1.

A person encounters emotional reactions every day, but rarely thinks about them. However, they make his life a lot easier. What does emotional release give a person? It helps keep your nerves in order. For this reason, those people who hide the manifestation of their emotions are more likely to suffer from heart failure and nervous diseases.

Definition

What is an emotional reaction? This is a process that is expressed in actions, words or state. It occurs in response to mental or external irritation. For example, someone scared you and you start to worry. Or someone gave you a surprise and you were happy. The emotional reaction to the same situation can be different between two people. Everything will depend on how one or another person views the current situation. Each person is the author of his own emotions, for this reason people can not only sincerely rejoice at something, but also fake their emotions. And sometimes the limits of decency force a person to restrain his feelings. But still, the real emotion and its simulated prototype will not escape the gaze of an attentive viewer.

Kinds

What types of emotional reactions are there? Conventionally, they can be divided into two groups. In the first, emotions are divided according to their positive connotation.

• Positive. A person has fewer positive emotions than negative ones. Is this due to the fact that there is not much pleasant in life? Not really. Historically, it so happened that a person felt good where he felt calm. And the calm flow of life does not evoke any vivid emotions.
• Negative. A person has more negative emotions than positive ones. This may be due to the fact that our ancestors spent a lot of time hunting and protecting themselves and their families. For this reason, they had many emotions associated with fear and irritation.

What other types can emotional reactions be divided into?

• Congenital. A person does not know what anger is from birth. This emotion is acquired. But even a baby knows what fear is.
• Learned. As the child develops, he explores the world and learns to express his emotions. Parents teach their child. They ensure that the child can react to a given situation in accordance with generally accepted norms.

Examples

What emotional reactions do you know? Below are the 6 main ones.

• Anger. This reaction occurs in the human soul when expectations do not coincide with reality. A person’s mood deteriorates and he begins to get irritated. To keep his nerves from getting worse, he spills everything out, most often on his interlocutor or on the one who happens to be closest.
• Joy. When a person is happy with something, he smiles and laughs. This reaction occurs to positive events.
• Yearning. Everyone experiences a sad state from time to time. Thanks to melancholy, a person can feel joy more keenly.
• Fear. This is an innate feeling that a person involuntarily experiences whenever he is in potential danger. The survival instinct is triggered, which warns of impending disaster.
• Astonishment. This emotional reaction can be both positive and negative. Everything will depend on the circumstances in which a person encounters surprise.
• Disgust. In a similar way, a person reacts to what is unpleasant to him. This emotion is acquired and formed under the influence of upbringing.

Degrees

Human emotional reactions develop in three directions. Conventionally, they can be characterized by three degrees.

• Rapidity. Each emotional reaction occurs with lightning speed, but a person does not know how long it will last. It all depends on how much this or that circumstance affects the person.
• Depth. Even if something has pissed off a person, the resentment can quickly pass, just like joy. But how strongly an emotion will strike a person will be determined by the depth of a particular person’s feelings for the person or object that caused the emotional reaction.
• Intensity. Some emotions are remembered for a long time, while others pass quickly. This is called the intensity of the reaction.

Types

Emotions are different, and so are human reactions. What does not interest a person passes quietly and does not touch the subtle strings of the soul. What is important to a person leaves a strong imprint. What types of emotional reactions are there?

• Emotional response. This reaction is considered the most standard and common. Something upsets you or makes you happy, you laugh or cry accordingly. Parents should develop the child's emotional reactions. If they don’t do this, it means their child will grow up to be an insensitive egoist.
• Emotional outburst. What does not fall under the definition of “response” can safely be called a flash. This is a short, strong reaction that leaves an imprint on a person’s soul. If you startle a friend unexpectedly and severely, you may see a clear example of an emotional outburst.
• Emotional explosion. This reaction, unlike a flash, is not lightning fast. It can occur as a result of a series of circumstances that alternately caused first an emotional response and then an outburst.

Functions

Why do people need emotional reactions and states?

• Regulatory. In order for the nervous system to function normally, it needs to discharge from time to time. Due to the outburst of emotions, tension is relieved and nerves return to normal.
• Estimated. A person does not have to test something through personal experience to understand whether it is good or bad. A person can imagine the emotions and reactions to them that he will experience in a given situation.
• Incentive. Some emotional reactions force a person to do something. If we take into account the truth of the saying that movement is life, then it is thanks to receiving specific emotions that a person can continue to move.
• Communicative. With the help of body language, a person can convey even more information than he can do verbally using words.

First reaction

A person can hide a lot from strangers, but not his feelings. Strong emotional disturbances are always conveyed through emotional reactions. An example of such behavior can be artificial smiles, which are commonly “put on” in society today. If your friend approaches you with a gloomy expression on his face, but his face changes when the person comes almost close, this means that the person is not very good-natured. On the face it is possible, but to an experienced eye the insincerity is immediately visible. As well as obvious joy, which betrays the sympathy of one person for another. If, when a person appears in a company of three people, one of them begins to smile broadly, then this is a clear sign of a caring attitude. So if you want to know how a person treats you, look at how he behaves when you appear.