The idea of variability is used in the field of genetics.
Variability is the property of that which is variable . This adjective, which comes from the Latin word variabĭlis , refers to what varies, changes or is modified .
For example: “The great climate variability today is a consequence of the pollution caused by humans” , “I recommend that you consult different banks before taking out the loan: there is a significant variability in the conditions according to the entity.” ” , “The variability of symptoms makes it a difficult disease to diagnose” .
Genetic variability
Genetic variability is the name given to the changes that occur in the genes of a species or population. This variability is a consequence of the process of natural selection , which develops when nature selects different alleles that are modified so that the species can evolve.
In this way, the greater the genetic variability, the greater the speed in the development of evolutionary changes. It is important to note that genetic variability can occur by combining genes or by mutation in a deoxyribonucleic acid ( DNA ) sequence. Let's see below these two sources of genetic variability that require sexual reproduction, in more detail:
Mutation
It is any change that takes place in a DNA sequence. Among the causes of this phenomenon are failures during replication, or the intervention of chemical substances or radiation found in the environment. It is important to note that a mutation does not necessarily affect the phenotype of a living being, that is, its biochemical, behavioral and physical traits.
This can be verified by observing that a DNA codon that has been modified to GGU from GGA encodes glycine, the same amino acid, meaning that it does not affect the phenotype. A codon, for its part, is the fundamental unit of information that is used to translate mRNA (messenger ribonucleic acid); It is a triplet of nucleotides, capable of encoding an amino acid.
On the other hand, there are numerous examples of mutations in which a modification of the phenotype does occur. In some of these cases of genetic variability, the resulting organism may not be suitable for survival , or its biological effectiveness may be reduced compared to that of its predecessor.
Stellar variability refers to changes in the brightness of stars.
Variability and combination of genes
Much of the hereditary differences can be explained by the combination of genes that occurs while gametes reproduce. It is important to note that in a homologous pair of chromosomes, each of them has independence to move during meiosis (one of the ways in which cells reproduce).
For this reason, the 23 pairs of chromosomes found in the human body are capable of giving 8,400,000 different combinations of genes . Another process that takes place at the same time as meiosis is called crossing over , and this increases the number of diverse genotypes that can arise as part of the offspring.
When recombination of alleles occurs in the context of sexual reproduction, they can give rise to highly diverse phenotypes, and this explains why this type of reproduction is an important source of genetic variability in so many populations.
Other uses of the concept
Stellar variability , on the other hand, refers to changes in a star 's brightness . These alterations take place over time in certain stars, although most of them maintain a stable luminosity. Stars that show variability are known as variable stars.
In an economy with inflation , finally, there will be variability in prices . A product that one day costs 10 pesos , a week later may cost 12 pesos and two weeks later, 16 pesos .