Do Mutations Increase or Decrease Genetic Variation?
Do mutations increase genetic variation?
Yes, mutations do increase genetic variations. Mutations that occur in the long run that is for hundreds to thousands to millions of years of time-frame do cause the introduction of new alleles and genes in a population. This causes genetic variation.
Actually, the very ultimate source of genetic variation is mutation. But, it is also to be noted that the various mechanisms such as sexual reproduction and genetic drift can also contribute to leading mutation.
We all know that mutation is one of the prominent forces of evolution that causes a change in the genetic sequence of an organism if occurred.
Mutations cause changes in the genetic sequence of an organism by causing insertions, deletions, or duplications of DNA sequences, and this causes a genetic sequence alteration or in other words, genetic variation.
So, if hereditary mutations occur, from one generation to the next then the occurance of genetic variation is almost ignorable.
Whereas, on the other hand, if hereditary mutations do occur in a time-frame of hundreds to thousands to millions of generations in a population then it will cause a significant amount of genetic variation in that population.
If the mutation has been occurring constantly at intervals over the course of millions of years of evolution and goes on continuing, or if the mutation had occurred on the genome for a long-time resulting in the production of proteins to stop, then in both of the cases, the production of new genes or alleles happens.
Production of new genes or alleles happens as mutation being the source of all genetic variations provides the raw materials on which the various evolutionary forces such as natural selection can act over the millions of years to form new genes or alleles.
Mutations can occur both in the gametic and somatic cells. Only those mutations that do occur in the gametic cells (egg or sperm cells) are passed to the future generations causing a great deal of genetic variation in the long-run.
Do mutations decrease genetic variation?
Mutations increase genetic variations as it causes changes in the genetic sequence. So, in no way, it can decrease genetic variation in a population. It will always increase genetic variation in a population.
Mutation causes genetic sequence changes leading to alteration of the genetic makeover of the organism in a population. This leads to alteration in the DNA sequence or nucleotide base with another nucleotide base.
If small hereditary mutations occur then, this will cause a little bit of an ignorable amount of changes in the genetic sequence.
Meanwhile, larger hereditary mutations can affect many genes on a chromosome if passed for several generations, and this can lead to the creation of new genes and alleles.
Mutations can be caused by substitution, insertions, deletions, or duplications of DNA sequences.
There are some mutations called silent mutations. Silent mutations don’t result in any kind of changes in the amino acid sequence of the encoded protein, although resulting in changes in the DNA sequence. Other mutations can result in abnormal protein product production.
In any way, mutations will cause the genetic sequence alteration that can be harmful, or useful, or of no use to the organism.
So, the concept is pretty much sure that mutations won’t decrease genetic variation but will always lead to an increase in genetic variation in the population.
What type of mutation will impact the most genes?
This answer is very hard to say that actually what type of mutation will impact the most genes.
If frameshift mutation occurs then this will eventually cause a big impact on the overall genetic makeover of the genes. On the other case, point mutations will only cause a small impact.
In a long time scale view, if we see various types of mutations occurring over many generations then the other evolutionary forces like natural selection, gene flow, etc. will act on those mutations. This will largely impact the most genes in a long time scale of thousands to millions of years.
Mutations are of various types that can happen in the organism’s genetic makeover. Some of these are substitution, insertion, deletion, inversion, duplication, translocation, and gene amplification types.
During all of the mutations, the DNA base sequence of the gene changes. That change can be like replacing a single nitrogenous base just like in point mutation type, or many nitrogenous bases at once just like in frameshift mutation type.
In simple words, if we say, the mutation will cause the alteration of the gene sequence. If it’s altering a single nitrogenous base just like in point mutation, then the impact is low.
And, if it’s altering many nitrogenous bases at once just like in frameshift mutation, then the impact on the gene will be pretty large.
And, when point mutation or frameshift mutation types occur over and over again and again for thousands to millions of generations then this will largely impact the most genes causing various great evolutionary changes in the population.
These evolutionary changes can be either useful, or harmful, or of no use to the organisms in that evolved population.
What actually is a good mutation?
Those mutations that eventually cause the formation of new versions of proteins that help organisms adapt to changes in their environment are known as good or beneficial mutations.
In order for any organism to evolve, adapt, and better survive in its environment it needs to undergo various changes in its ancestral lineage.
For such changes to occur, the mutation is one of the evolutionary factors that play a key role. And, the occurring mutations can be either useful, or harmful, or of no use to the organism.
Good or beneficial mutations are those where the occurring mutations do lead to various beneficial changes in the organisms over the long timescale.
Good mutations are significantly essential for evolution to occur and do highly contribute in the organism’s chances of surviving or reproducing, so they are likely to become more common over time and continue their lineage.
And it is to be highly noted that not all mutations are beneficial. Mutations occurring in a population can be a mix of harmful, good, or useless mutations.
It’s when good mutations occur and get passed to the future generations by means of germ cells than that cause great adaptations in the organism and its future generations to better survive, reproduce, and evolve drastically.
The genetic mutation that drives evolution is random. But there’s a list of many beneficial mutations that are known to exist even in human beings as well that have been well-studied so far.
Natural selection is one of the prominent evolutionary forces that may take up the changes caused due to good beneficial mutations over a course of a long timescale and cause it to spread throughout the population.
For example, Malaria resistance in the population of the African country of Burkina Faso is due to the presence of a different variant of hemoglobin, named HbC in their blood.
In Hemoglobin C (HbC), the glutamic acid residue at the 6th position of the β-globin chain is replaced with a lysine residue. This replacement is due to a point mutation in the HBB gene. That’s also why HbC is also called abnormal hemoglobin.
It has been well-studied so far that the people with just one copy of HbC (mutated HBB gene) are 29% less likely to get malaria, while people with two copies of this gene enjoy a 93% reduction in risk.
So, it is pretty much clear-cut that Malaria resistance in the population of the African country of Burkina Faso is a cause due to Good Mutation as it provides the population with Malarial resistance ability.
Difference: Genetic Variation Vs. Mutation
Genetic variation is the diversity in the gene frequencies of a population. Genetic variation can be the differences between populations or between individuals of the same population.
Without genetic variation, evolution is not possible from the molecular biological point of view. Genetic variation is caused by variation in the order of bases in the nucleotides of the genes.
Genetic variation can occur in germ cells (sperm and egg) or somatic cells. Only the genetic variations occurring in germ cells can be inherited from one individual to another causing evolution.
Genetic variation causes to vary every individual from each other phenotypically or genotypically.
Mutations cause genetic sequence changes in the organism. Mutations are the original source of genetic variation causing a permanent alteration to the DNA sequence.
Not only mutation, but there are multiple sources of genetic variation like genetic recombination, sexual reproduction, and genetic drift. Mutation is one of the significant and original sources of genetic variation.
Mutations can occur due to DNA replication error, exposure to harmful chemicals and UV radiation, ionizing radiations, radioactive rays, chemical mutagens, x-rays, etc.
A few mutations that occur can be fixed during DNA replication, but those that are permanent and arising in the gametic cells are passed on to the next generations causing genetic variations over a long time-frame along with the help of other evolutionary forces like natural selection.
Mutations have been known to occur randomly and regularly, and so over the long run is one of the key reasons for differentiation, genetic variation, and evolution within and between the populations.
|1.||Genetic Variation leads to changes in the allele or gene frequencies in a population.||Mutation causes a permanent change in the genetic sequence of an organism.|
|2.||Genetic variation can occur due to mutation, reproduction, genetic drift, gene flow, environmental factors, natural selection, etc.||Mutation is one of the original sources of genetic variation that can occur due to smoke, chemicals, ionizing radiations, radioactive rays, chemical mutagens, or x-rays.|
|3.||Genetic Variation varies from gene to genome, from one organism to another.||Mutation also varies from gene to genome, from one organism to another.|
|4.||Genetic variations are seen in groups or populations of an individual.||Mutations affect the single organism.|
|5.||Genetic variation can occur both randomly or non-randomly.||Mutations always occur randomly.|