The 8 differences between genotype and phenotype
The existence of humans and of any other living being on the face of the Earth is possible only and exclusively thanks to one thing: genes. In these portions of DNA the genetic information is encoded so that the cells of our organism fulfill their functions.
Human beings are the result of the sum of the 30,000 genes of our genome. In them are all the instructions that determine our physiology. But is there nothing else that comes into play? Are we simply the result of a sum? No. Fortunately, biology is much more than genes.
Genetic expression is determined by many factors, so our genes are expressed in a particular way depending on what happens around us and it is even possible that certain genes are silenced or activated.
In reality, we are the consequence of the interaction between our genes and the environment.. This is the mainstay of genetics. Therefore, in today's article, we will answer all the questions you may have regarding differences between two related but very different concepts: genotype and phenotype. Let's go there.
What is the genotype? And the phenotype?
We have prepared a selection of the differences between the two concepts in the form of key points, but we consider it interesting (and important), as a context, to define exactly what is the genotype and what is the phenotype of a living being. In this way, their differences will begin to become very clear. Let's get started.
The genotype: what is it?
The genotype is, broadly speaking, the genetic information that a living being possesses in the form of DNA (although certain viruses can have it in the form of RNA, but it is an exception). In other words, the genotype of a living being is the set of genes of its genome.
In this sense, the genotype is the collection of genes of an organism. In the case of human beings, our genotype would be the set of 30,000 genes present in each of our cells, each one having its variations and polymorphisms that make, at the genetic level, we are all unique.
These genes are organized into what we know as chromosomes., which are each one of the highly organized structures that contain most of our genetic material together with proteins and other molecules that provide stability. In the case of humans, we have 23 pairs of chromosomes.
And it is in these 46 chromosomes present in the nucleus of our cells that our genotype hides. This genotype, which is the succession of genes (which, in turn, are each of the portions of DNA that code for a specific cellular process) of our genome, is like an instruction book.
In it, is the recipe for what we are. Or rather, of what we can be and what we cannot be. And it is that the genes of the genotype, to have influence at the physiological level, must be expressed in the form of proteins.
But are all the genes of our genotype expressed? And those who express themselves, do they always do so with the same intensity? No. And this is the magic of genetics. Genetic expression is an incredibly complex world, but it is enough to understand that, depending on the internal and external conditions (of the environment) perceived by our cells, the regulatory genes will coordinate the expression (or silencing) and the intensity in said expression of our genes. . And when the genotype is expressed, we stop talking about the genotype and move on to talking about the phenotype.
The phenotype: what is it?
The phenotype is, broadly speaking, the set of physiological characteristics that an organism presents as a result of genetic expression modulated by the environmental and internal conditions of the body. In other words, is the result of the interaction between genotype and environment. It is the set of observable traits of an individual derived from the selective expression of its genotype.
In this sense, the phenotype of an individual is determined by the expression of its genotype based on the environment to which it is exposed. The environment shapes our genetic expression. And depending on what happens around us, some genes will be silenced and others will be activated, thus shaping who we are.
The phenotype is the set of observable traits that are due to the regulated expression of genes depending on the environment and that have manifestations not only physical, but also behavioral. As we have seen, the genotype is the ingredients. The phenotype is the dish that we get after the environment (the chef) has cooked it.
Therefore, you are a phenotype. Or, rather, a set of many phenotypic traits. You are not a genotype. You are not the result of a sum of genes. You are the result of how these genes interact with the environment and the consequence that some are activated and others are silenced.
This explains why two identical twins, despite sharing the same genotype (their genes are the same), having a different genetic expression, are not exactly identical. Their phenotypes, having lived different lives, are also different. We all have a unique phenotype.
How are genotype and phenotype different?
After defining both concepts, surely the differences between genotype and phenotype have become more than clear. Even so, to make the information available to you more clearly and concisely, we have prepared a selection of its most important differences in the form of key points. Let's go there.
1. The phenotype is the result of the interaction between genotype and environment
The most important difference and from which all the others derive. As we have seen, the phenotype is the result of the interaction between the genotype (the sequence of genes on our chromosomes) and the environment, understood as internal conditions (what happens inside our body) and external conditions (what happens outside the body). Body).
Therefore, while the genotype is "simply" the set of our genes, the phenotype is the result of how these genes are activated or silenced depending on what happens in the environment.
2. The phenotype is observed; the genotype; not
The phenotype is the set of traits observable at the physiological or behavioral level of the selective expression of genes, while the genotype is the sequence of genes present in our cells. Therefore, while a phenotype can be seen with the naked eye (your eye color, your height, your nose shape, your behavior, your ears, etc.), the genotype cannot be observed. Unless you sequence your DNA. But it is not something usual, really.
3. There can be two identical genotypes; but not two identical phenotypes
In the vast majority of the population, both our genotype and our phenotype are unique. There is no one with our same genes (genotype), much less with the same observable genetic expression (phenotype).
Even so, in the case of identical twins, they do have the same genotype (not counting the inevitable random mutations that make them not exactly the same), but since their genetic expression is different since their internal and external environment is different, they do not have the same phenotype. Namely, there are cases in which two people can have the same genotype (identical twins), but there will never be two people with the same phenotype.
4. The genotype is DNA; phenotype, physiological traits
The genotype is a sequence of genes. It is the set of portions of DNA that determine our genome. It's just that: nucleotides. Instead, the phenotype is all the incredible variety of physiological traits that derive from the modulated expression of this DNA: height, eye color, complexion, hair, nose shape, ear size, fingerprints, skin tone, etc.
5. The phenotype varies throughout life; the genotype, no
It is evident that our phenotype changes throughout life. You are not the same with 1 year of life as with 80 years. Genetic expression changes over time, so the observable phenotype does too. Instead, the genotype never changes. We are born with some genes and we die with the same genes. What varies is how and how much they are expressed.
Even so, a point must be made. And it is that although this serves to understand it, it is not entirely true. Genes, with each cell division, inevitably undergo mutations, that is, genetic errors. Therefore, although in a "genetically ideal world" we would die with the same genes with which we were born, in practice, this is not So.
6. The genotype is not moldable; the phenotype, yeah
Whatever happens, leaving aside these phenomena of random mutations that we have already discussed, your genes will always be the same. You will not change your genes depending on what happens around you. But your phenotype is shaped by the environment. We cannot choose our ingredients (genes), but we can choose which dish (phenotype) we make with them. Obviously, there are many environmental factors that we cannot control, but the idea is understood.
7. The genotype is inherited; the phenotype, no
The genes that make up our genome come from the union between the male (sperm) and female (ovum) sex gametes of our father and mother, respectively. Therefore, our genotype is the result of recombination between the genes present in these gametes. The genotype, then, is inherited. The phenotype, on the other hand, despite the fact that we will always be determined by the inherited genes, is not inherited. It will depend on how these genes are expressed depending on what we do in life and what happens to us.
8. The phenotype depends on the environment; the genotype, no
Finally, a difference that serves as a conclusion to everything we have seen. The genotype does not depend on the environment, or what you do or what happens to you in life. The genotype is just the sequence of genes within your cells. The phenotype, on the other hand, is the result of how the expression of these genes is modulated as a function of the environment. You can't control which genes you have, but you can (to some extent) what to do with them.