Can mutations create new genes?
Yes, mutations can create new genes. Mutations cause changes in the DNA sequence of the gene which can be due to the duplication of large sections of DNA.
So, the duplication and mutation of an ancestral gene, or by recombining parts of different genes causes to form new combinations with new genes with all new functions.
Such changes on the gene act as a source on which various evolutionary forces like natural selection, etc. works for evolving new genes over the course of millions of years.
The mutation is a bit of a process that occurs at the molecular level of the DNA that changes the alignment and occurrence of the nitrogenous bases of the genome.
In a broad sense, you can say that mutation changes the DNA or genome structure.
Mutation can occur due to genetic recombination during cell division in both the somatic and gametic cells of the biological body.
It can also occur due to exposure to UV radiation, viral replication, mitosis, or meiosis or other types of damage to DNA (such as pyrimidine dimers, etc.)
Such mutations can either signal the altered genome to produce a different kind of proteins that functions differently in the body. Mutations can also direct the stopping of proteins production of the altered genome.
So, the mutation can either stop the production of protein from the altered (mutated) genome or can signal the production of a different kind of protein that can be helpful or harmful for the body.
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 time and have now stopped the production of proteins, then in both of the cases, the production of new genes happens.
Production of new genes happens as mutation being the source of all genetic variations provides the raw material on which evolutionary forces such as natural selection can act over the millions of years to form new genes.
Now, it is also to be pretty much cleared that not all type of mutations can create new genes at the same time duration. So, the probability of mutations causing the formation new genes is not 100%.
So, reading this, it can be stated that mutations can actually create new genes, but not all of the time.
And so, not all mutations lead to evolution. Only hereditary mutations, which occur in egg or sperm cells, can be passed to future generations and potentially contribute to an evolution in more occurrence (probability).
Can mutation create a new allele?
Gene is a broader term than allele. In simple words, a gene is a functional piece of DNA for a specific trait, while alleles are a different variation of that gene.
A gene makes a protein while alleles produce different phenotypes related to what the gene makes. Gene is a single unit for one trait while the alleles occur in pairs.
So, it is pretty much clear that a gene can have two or more alleles. Each allele is a different version of the same gene.
For example: The gene for eye color can have allele for back eye, grey eye, or brown eye.
Yes, mutations can create a new allele (variation of the gene) by altering the nucleotide sequence of the gene. Just like the concept that mutation creates new genes, the thing is same for the concept that mutations can also create new alleles of the gene.
The chances (probability) of creating new alleles of the same gene is more than creating all new genes with all new alleles.
This is because a little bit of mutation over a hundred to thousands of years can create a new version of a gene. While mutation over millions of years of evolution results in the formation of new genes with all new alleles.
Such mutations causing the formation of a new allele can occur either in the somatic cell or majorly in the gametic cell during cell division.
For example, a butterfly may produce offspring with new mutations occurring in the gametic cells during meiosis. The majority of these mutations will have no effect; but one might change the color of one of the butterfly’s offspring, making it harder (or easier) for predators to see. If this color change is advantageous, the chances of this butterfly’s surviving and producing its own offspring are a little better, and over time the number of butterflies with this mutation may form a larger percentage of the population.
So, with this example, it can be clearly understood that the color of the butterfly’s offspring changed due to the formation of a new allele as a result of mutations that had occurred in the body color gene of the parent butterfly. That new allele expressed itself giving a new body color to the offspring because it became dominant.
It is also to be noted that an allele of the gene is only expressed when it becomes dominant and not recessive.
So, it may also be the case that an all new allele is formed but that allele is not expressed because that is in its recessive condition in the offspring, but it can pass on to the future generations by gametes and can become dominant expressing the trait.
How creating new genes from mutation is the reason for evolution?
Evolution demands changes in the biological body to adapt to new things in its surroundings. Due to evolution, populations of organisms change over generations with various adaptations.
Notably, genetic variations underlie these changes. Meaning, that evolution is possible because various genetic changes have taken place in the organism’s body that had led to the formation of new alleles of the same gene, or new genes with new different alleles, or have shut down the ancestral genes.
In general, genetic variations naturally arise from gene mutations or from genetic recombination during mitosis or meiosis. It can also occur due to other factors as well such as exposure to UV radiations, pyrimidine dimers formation, etc.
Now, it is also to be noted that, the mutated genes need to be hereditary in order to pass the genetic variations to the future generations, generation after generation. This causes notable evolution over the long run.
Now, if the genetic variation is not hereditary then evolution can’t pass to the future generations, and so, as such evolution due to mutation is less likely to happen.
So yes, mutation is the reason for evolution, but that mutation leading to evolution is possible when the mutated genes are hereditary and is successfully passing from one generation to the next over the course of millions of years.
Now, one thing is also to be noted that, if the mutated gene produces a function or adaptation that is harmful then the evolutionary processes like natural selection, etc. will likely eradicate that harmful mutated gene in the future generations.
Or else, if the mutated gene is well-to-do by producing great adaptations that are good for the survival of the offspring then the evolutionary processes like natural selection, etc. will likely conserve and frame that useful gene causing useful evolutions after millions of years.
Where do new genes come from?
New genes can come from ancestral genes due to the cause of genetic variations. Genetic variations can not only occur due to mutation but also due to random mating, random fertilization, including recombination between homologous chromosomes during meiosis.
This genetic variation is actually the difference in DNA’s nucleotide sequence among individuals at the molecular level or the differences between populations phenotypically at the population level.
The three main types of evolution viz. the divergent, convergent, and parallel evolution occurs supporting the creation of new genes from ancestral genes by getting influenced by the evolutionary factors viz. natural selection, random genetic drift, mutation, population mating structure, and culture.
It is also important to note that, new genes can also come from non-coding regions of DNA called the junk DNA through evolution.
It is also informative to note that new genes can also arise from existing genes through duplication and divergence.
The process of duplication and divergence happens when DNA copying mechanisms accidentally leave behind an extra copy of a particular gene which later on replicates and evolves forming a new gene with all new functionality.
Over recent years, scientists have also proposed and explained several experimental and theoretical mechanisms by which new genes are generated. These include gene duplication, transposable element protein domestication, lateral gene transfer technology, gene fusion, gene fission, and de novo origination.
So, it is pretty much clear-cut that the formation of new genes is a primary driving force of evolution in all organisms and had, has, and will be occurring. And that, evolution demands changes that can’t be possible without new gene formation.