What is a phenotype? Phenotype and genotype - their differences

This is what “parsley” looks like, to say the least. Once again I am faced with the fact that the fundamental concepts of genetics are presented in textbooks in such a way that it can be difficult to understand them.

I was tempted to call this article that way at first "Phenotype and genotype." It is clear that the phenotype is secondary to the genotype. But if students can most often interpret the term “genotype” correctly, then as it turns out, there is no clear idea regarding the concept of “phenotype”.

But how can it be “clear” if the definitions of the phenotype are educational literature are so vague.

"Phenotype- the totality of all external characteristics of an organism, determined by genotype and conditions environment" Or “Phenotype is the totality of all external and internal characteristics and properties of an organism, depending on the genotype and environmental conditions.”

And if there really are both “external” and “internal”, and this is actually the case, then what is the difference between a phenotype and a genotype?

Still, you have to start not from the “tail”, but from the “head”. I am sure that a couple of minutes will pass and you, having somewhat clarified for yourself what the “genotype of an organism” is, will be able to get a clearer idea of ​​the “phenotype”.

We often use the terms “trait” and “gene” as synonyms.

They say that “a genotype is the totality of all the characteristics of an organism.” And here it is important to understand the most important thing - it is precisely in the determination of the genotype that such a definition introduces additional confusion. Yes, indeed, information about any trait is encoded in any gene (or set of genes) of the organism.

But there are a lot of genes, the entire genotype of an organism is huge, and during the life of a given individual or individual cell, only a small part of the genotype is realized (that is, serves to form any specific characteristics).

Therefore, it would be correct to remember that "genotype- the totality of all genes organism." And which of these genes are realized during the life of the organism in its phenotype, that is, will serve the formation of any signs- this depends both on the interaction of many of these genes and on specific environmental conditions.

Thus, if we correctly understand what a genotype is, then there is no loophole for confusion in terms of what is a “genotype” and what is a “phenotype”.

It is clear that “a phenotype is the totality of all genes realized during the life of an organism that served to form specific signs of a given organism under certain environmental conditions.”

Therefore, throughout the life of an organism, under the influence of changing environmental conditions, the phenotype can change, although it is based on the same unchanged genotype. And within what limits can the phenotype change?

Reaction rate

These boundaries for the phenotype are clearly delineated by the genotype and are called “reaction norms.” After all, nothing can appear in the phenotype that was not already “recorded” earlier in the genotype.

To better understand what is included in the concept of “reaction norms”, let’s look at specific examples possible manifestation of a “broad” or “narrow” reaction norm.

The weight (mass) of the cow and the milk yield of the cow, which trait has a wider and which has a narrower reaction rate?

It is clear that the weight of an adult cow of a certain breed, no matter how well it is fed, cannot exceed, for example, 900 kg, and if it is poorly maintained, it cannot be less than 600 kg.

What about milk yield? With optimal housing and feeding, milk yield can vary from some maximum possible value for a given breed; it can drop to 0, under unfavorable housing conditions. This means that the mass of a cow has a rather narrow reaction rate, and the milk yield is very wide.

Example with potatoes. It is obvious to anyone that the “tops” have a rather narrow reaction rate, and the mass of tubers has a very wide one.

I think everything has settled down now. The genotype is the set of all the genes of an organism; this is its entire potential of what it can be capable of in life. And the phenotype is only a manifestation of a small part of this potential, the implementation of only part of the organism’s genes into a number of specific characteristics during its life.

A clear example of the transformation of part of its genotype into a phenotype during the life of an organism are identical twins. Having absolutely the same genotype, in the first years of life they are almost indistinguishable from each other phenotypically. But as they grow up, having at first minor differences in behavior, in some attachments, giving preference to one or another type of activity, these twins become quite distinguishable phenotypically: in facial expression, body structure.

At the end of this note, I would like to draw your attention to something else. The word genotype for students of the basics of genetics has two meanings. Above we examined the meaning of “genotype” in its broad sense.

But to understand the laws of genetics, when solving genetic problems, the word genotype means only a combination of some specific individual alleles of one (monohybrid crossing) or two (dihybrid crossing) pairs of certain genes that control the manifestation of a specific one or two traits.

That is, our phenotype is somehow truncated, we say “the phenotype of an organism,” but we ourselves have studied the mechanism of inheritance of only one or two of its characteristics. In a broad sense, the term “phenotype” refers to any morphological, biochemical, physiological and behavioral characteristics of organisms.

P.S. In connection with the characteristics of the concepts “genotype” and “phenotype,” it would be appropriate here to examine the question of hereditary and non-hereditary forms of variability in organisms. Well, okay, that’s exactly what we’ll talk about in.

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Today experts pay Special attention phenotyping. They are able to “figure out” a person in a matter of minutes and tell a lot of useful and interesting information about him.

Phenotype features

Phenotype is all the characteristics in general that are inherent in an individual at a certain stage of his development. Thus, we can safely say that a person’s phenotypes can change throughout his life.

Every trait or characteristic of a living thing that is observed defines a person's phenotype. Signs of a phenotype are the characteristics of a person:

• development;
• morphology;
• physiological characteristics;
• biochemical properties;
• behavior, etc.

Phenotypes are initially formed under the influence of the genotype. Environmental factors also influence. The phenotype also includes clinically determined factors:

• height;
• blood type;
• hair color and type;
• eye color.

Phenotypology

Phenotypology is relative new science, which is capable of expressly diagnosing a person’s character based on his external signs.

We can safely say that phenotype is the appearance of genetics. A person who has mastered phenotypology can quickly and easily read many of his personal characteristics, character.

Phenotypology is " powerful weapon", which will be useful to every person in the business industry, sales, education, etc.

Phenotypology is a science that talks about the relationship between psychophysiological and psychophysical characteristics in human behavior, based on individual characteristics of the personality phenotype.

A phenotype is all the characteristics of a biological individual at a specific moment in his life. Formation occurs with the participation of the genotype under the influence of the environment. Thus, the phenotype is a different realization of the genotype in each specific case.

The author of phenotypology, Mark Lucini, identified about 140 main characteristics of the phenotype. Various experts number them up to 10 to the 30th power. This indicates that every person is individual personality. Now we can safely say that the ratio of phenotypes may be different.

A full range of skills and knowledge in phenotyping can be acquired in training course from 30 to 55 academic hours.

Possibilities of phenotyping

In 4 minutes, a person trained in phenotypology can identify the following character traits:

• direction and degree of mania;
• limits, prospects and orientation of the genetic potential of intelligence;
• characteristics of sexuality, taking into account the tendency towards perversion or carnivorous sensations;
• moral characteristics of a person (honesty, meanness, devotion, deceit, duplicity, etc.);
• a person's genetic tendency to non-standard actions, taking into account crime;
• human will (the ability to resist aggression, defend one’s point of view, etc.);
• a tendency to heroism and extravagant actions (including a tendency to murder, heroism, suicide, etc.);
• threshold of irritability, quality of the nervous system;
• tendency towards moralism;
• incapacity, capacity;
• cowardice, courage, secrecy;
• stubbornness;
• thirst for authority, preoccupation with one’s appearance;
• attentiveness, suspicion, insight;
• practical, commercial, predatory and business inclinations;
• and so on, a total of 140 qualities

The accuracy of the results after work by specialists is 80-95%.

Is knowledge about phenotypes necessary?

In fact, knowledge of phenotypology is necessary for every person. After all, we live in society, which means we are constantly surrounded by society.

Where is phenotypic knowledge especially important?

1. Various personnel audits, including people who have high degree access to important, classified information.
2. Sales, negotiations, communication and purchasing.
3. Forensics.
4. Upbringing.
5. Social and political sphere.
6. Analysis of historical figures.
7. Decoding the actions of people who have already died.
8. Development of stage images of various literary characters.
9. Selection of a competent image.
10. Psychological makeup.

Conclusion

A phenotype is the totality of all characteristics that are inherent in an individual at a certain stage of development. Knowledge about the phenotype allows us to characterize a person and his character traits in a minimum amount of time.

Genetics has repeatedly amazed us with its achievements in the field of studying the genome of humans and other living organisms. The simplest manipulations and calculations cannot do without generally accepted concepts and signs, which this science is not deprived of.

What are genotypes?

The term refers to the totality of genes of one organism, which are stored in the chromosomes of each of its cells. The concept of genotype should be distinguished from genome, since both words have different lexical meanings. Thus, the genome represents absolutely all the genes of a given species (human genome, monkey genome, rabbit genome).

How is a person's genotype formed?

What is a genotype in biology? Initially, it was assumed that the set of genes of each cell in the body is different. This idea was refuted from the moment scientists discovered the mechanism of formation of a zygote from two gametes: male and female. Since any living organism is formed from a zygote through numerous divisions, it is not difficult to guess that all subsequent cells will have exactly the same set of genes.

However, it is necessary to distinguish the genotype of the parents from that of the child. The fetus in the womb has half the set of genes from mom and dad, so although children are similar to their parents, at the same time they are not 100% copies of them.

What are genotype and phenotype? What is their difference?

Phenotype is the totality of all external and internal characteristics of an organism. Examples include hair color, presence of freckles, height, blood type, amount of hemoglobin, synthesis or absence of an enzyme.

However, the phenotype is not something definite and constant. If you observe hares, the color of their fur changes depending on the season: in summer they are gray and in winter white.

It is important to understand that the set of genes is always constant, but the phenotype can vary. If we take into account the vital activity of each individual cell of the body, each of them carries exactly the same genotype. However, insulin is synthesized in one, keratin in the other, and actin in the third. Each one is different from each other in shape, size and function. This is called phenotypic manifestation. This is what genotypes are and how they differ from the phenotype.

This phenomenon is explained by the fact that during the differentiation of embryonic cells, some genes are turned on, while others are in “sleep mode”. The latter either remain inactive throughout their lives or are reused by the cell in stressful situations.

Examples of recording genotypes

In practice, the study is carried out using conditional gene encryption. For example, gene brown eyes write down capital letter"A", and the manifestation blue eyes- small letter "a". This shows that the trait of brown eyes is dominant, and blue is recessive.

So, based on the characteristics, people can be:

• dominant homozygotes (AA, brown-eyed);
• heterozygotes (Aa, brown-eyed);
• recessive homozygotes (aa, blue-eyed).

Using this principle, the interaction of genes with each other is studied, and usually several pairs of genes are used at once. This raises the question: what is genotype 3 (4/5/6, etc.)?

This phrase means that three pairs of genes are taken at once. The entry will be, for example, like this: АаВВСс. Here new genes appear that are responsible for completely different characteristics (for example, straight hair and curls, the presence of protein or its absence).

Why is the typical genotype record arbitrary?

Any gene discovered by scientists has a specific name. Most often this English terms or phrases that can reach considerable lengths. The spelling of names is difficult for representatives of foreign science, so scientists have introduced a simpler entry for genes.

Even a student high school sometimes may know what genotype 3a is. This notation means that a gene is responsible for 3 alleles of the same gene. If the real gene name were used, understanding the principles of heredity might be difficult.

If we're talking about about laboratories where serious karyotype studies and DNA studies are carried out, then they resort to official names genes. This is especially true for those scientists who publish the results of their research.

Where are genotypes used?

Another one positive trait use simple notation- this is versatility. Thousands of genes have their own unique name, but each of them can be represented by just one letter Latin alphabet. In the vast majority of cases, when solving genetic problems on different signs the letters are repeated again and again, and each time the meaning is deciphered. For example, in one problem, gene B is the color of black hair, and in another, it is the presence of a mole.

The question “what are genotypes” is raised not only in biology classes. In fact, the convention of designations causes the vagueness of formulations and terms in science. Roughly speaking, the use of genotypes is mathematical model. IN real life everything is more complicated, despite the fact that general principle Still managed to transfer it to paper.

By by and large genotypes in the form in which we know them are used in school and university education when solving problems. This simplifies the understanding of the topic “what are genotypes” and develops students’ ability to analyze. In the future, the skill of using such a notation will also be useful, but for real research, real terms and gene names are more appropriate.

The genes are currently being studied in various biological laboratories. Encryption and use of genotypes is relevant for medical consultations when one or more characteristics can be traced over a number of generations. As a result, experts can predict the phenotypic manifestation in children with a certain degree of probability (for example, the appearance of blond hair in 25% of cases or the birth of 5% of children with polydactyly).

The word "phenotype" has Greek origin and is translated (literally) “I discover”, “I manifest”. What is it like practical significance this concept?

What is a phenotype? Definition

Phenotype should be understood as a set of characteristics that are inherent in an individual specific stage development. This set is formed on the basis of the genotype. Diploid organisms are characterized by the manifestation. More precisely, defining what a phenotype is, we should talk about the totality of internal and external characteristics of the organism that were acquired in the process

General information

Despite the fairly accurate phenotype, its concept has a number of uncertainties. Most structures and molecules that are encoded genetic material, are not detected in the external appearance of the organism. Moreover, they are part of the phenotype. An example is the blood phenotype of humans. In this regard, according to a number of authors, the definition should include those characteristics that can be obtained using diagnostic, medical or technical procedures. A more radical further expansion may include acquired behavior, and, if necessary, the influence of the organism on the environment and other organisms. So, for example, incisors can be taken for their phenotype.

Main characteristics

When defining what a phenotype is, we can talk about some “carrying out” of genetic information towards environmental factors. As a first approximation, two characteristics should be considered:

1. Dimensions of the phenotype. This sign indicates the number of “removal” directions, which characterizes the number of environmental factors.
2. The second sign indicates the level of sensitivity of the phenotype to environmental conditions. This degree is called range.

Taken together, these characteristics indicate the richness and variety of the phenotype. The more multidimensional the set individual characteristics, the more sensitive the traits and the further they are from the genotype, the richer it is. So, for example, if you compare the phenotype of a bacterium, roundworm, frog, or human, then the “richness” in this chain increases. This means that the human phenotype is richer.

Historical reference

In 1909, Wilhelm Johansen (a Danish scientist) for the first time, in conjunction with the concept of genotype, proposed a definition of phenotype. This made it possible to distinguish heredity from the result of its implementation. The idea of ​​differences can also be traced back to the work of Mendel and Weissmann. At the same time, the latter distinguished somatic and reproductive cells in The chromosome set received from the parents is contained in Chromosomes carry a complex of genes characteristic of specific type in general and a certain organism in particular. Genes contain information about proteins that can be synthesized, as well as about the mechanisms that, in fact, determine and regulate synthesis. What happens then? During ontogenesis, genes are sequentially turned on and the proteins encoded by them are synthesized. As a result, the formation and development of all the properties and characteristics of the organism that make up its phenotype occurs. In other words, a certain “product” is obtained from the implementation of the genetic program contained in the genotype.

The influence of external conditions on the development of individual characteristics

It should be noted that the genotype is not a clear factor determining the phenotype. To one degree or another, the formation of a set of individual characteristics will also depend on the environment, that is, on external factors. IN different conditions the phenotypes are sharply different. For example, the species of butterflies "Arashnia" produces two offspring per year. Those individuals that emerged from overwintered pupae (spring ones) differ sharply from those that appeared in summer time. The phenotype of the plant may also differ. For example, in open space pine trees are spreading, but in the forest they are slender and tall. In the water buttercup, the shape of the leaf depends on where it is located - in the air or in the water.

Relationships between phenotypes and genotypes

The ability to change, which is provided by the genetic program, is called the reaction norm. As a rule, the more diverse the conditions in which a species lives, the wider this norm. In the case when the environment differs sharply from the one to which the species is adapted, a disruption occurs in the development of organisms and they die. Phenotype traits do not always reflect recessive alleles. But at the same time they are preserved and can be passed on to offspring. This information allows us to better understand the evolutionary process. Only phenotypes are involved, while genotypes are transmitted to the offspring and remain further in the population. The interaction is not limited to the relationship between recessive and dominant alleles - many genes interact with each other.

Genotype– a set of hereditary characteristics and properties received by an individual from its parents. As well as new properties that appeared as a result of gene mutations that the parents did not have. The genotype is formed through the interaction of two (egg and sperm) and represents a hereditary development program, being whole system, and not a simple sum of individual genes. The integrity of the genotype is the result of development, during which all genes were in close interaction with each other and contributed to the preservation of the species, acting in favor of stabilizing selection. Thus, a person’s genotype determines (determines) the birth of a child, a hare’s offspring will be represented by hares, and only a sunflower will grow from a sunflower.

Genotype– it’s not just the sum of genes. The possibility and form of gene manifestation depend on environmental conditions. The concept of environment includes not only the conditions surrounding the cell, but also the presence of other genes. Genes interact with each other and, once in one, can greatly influence the manifestation of the action of neighboring genes.

Phenotype- the totality of all signs and properties of the organism that have developed in the process individual development genotype. This includes not only external signs(skin color, hair, ear or nose shape, flower color), but also internal: anatomical (body structure and mutual arrangement organs), physiological (shape and size of cells, structure of tissues and organs), biochemical (protein structure, enzyme activity, concentration of hormones in the blood). Each individual has its own characteristics appearance, internal structure, the nature of metabolism, the functioning of organs, i.e. your phenotype, which was formed under certain environmental conditions.

If we consider the results of self-pollination F2, we can find that plants grown from yellow seeds, although externally similar and having the same phenotype, have a different combination of genes, i.e. different genotype.

Concepts genotype and phenotype– very important in . The phenotype is formed under the influence of the genotype and environmental conditions.

It is known that the genotype is reflected in the phenotype, and the phenotype is most fully manifested under certain environmental conditions. Thus, the manifestation of the gene pool of a breed (variety) depends on the environment, i.e. conditions of detention ( climatic factors, care). Often varieties developed in some areas are not suitable for cultivation in others.