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What is the difference between multiple allelism and polymorphism?
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Matthew Arslan
What is the difference between multiple allelism and polymorphism?
This answer refers to polymorphism within genetics (for clarification), which as far as I know is the more common use of the term (but that could just be because I'm a geneticist).
Polymorphism in general refers to genetic variation of traits within a population (or species), due to mutations.
A 'single nucleotide polymorphism' is a single change in the DNA sequence of an organism at some point. So:
A -> C
or
T -> G
Or some other combination of these. It is simply a change of a single nucleotide. More specifically, a SNP is present in at least 1% of a given population.
As these mutations (and other types of mutations) accumulate it results in multiple allele variants of a gene.
This answer refers to polymorphism within genetics (for clarification), which as far as I know is the more common use of the term (but that could just be because I'm a geneticist).
Polymorphism in general refers to genetic variation of traits within a population (or species), due to mutations.
A 'single nucleotide polymorphism' is a single change in the DNA sequence of an organism at some point. So:
A -> C
or
T -> G
Or some other combination of these. It is simply a change of a single nucleotide. More specifically, a SNP is present in at least 1% of a given population.
As these mutations (and other types of mutations) accumulate it results in multiple allele variants of a gene.
unless it means that two alleles may not result in two different phenotypes?
That is correct. Due to codon degeneracy.. ie one amino acid can be encoded by more than one set of 3 DNA base pairs... you can a difference in DNA but no difference in the protein. This synonymous base changes leads to no phenotype.
Also it is possible for an amino acid change to occur in a protein and cause no phenotype either, as the change may occur in a region that has no over effect on the protein function, folding and interaction with other proteins.
So as you have eluded too, not all allelic variation leads to a phenotypic variation.
unless it means that two alleles may not result in two different phenotypes?
That is correct. Due to codon degeneracy.. ie one amino acid can be encoded by more than one set of 3 DNA base pairs... you can a difference in DNA but no difference in the protein. This synonymous base changes leads to no phenotype.
Also it is possible for an amino acid change to occur in a protein and cause no phenotype either, as the change may occur in a region that has no over effect on the protein function, folding and interaction with other proteins.
So as you have eluded too, not all allelic variation leads to a phenotypic variation.
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The term polymorphism is broad and can have different meanings. Here are your definitions
Multiple Allelism: The existence of more than two alleles of the same gene within a population.
Polymorphism: the occurrence of more than two distinct phenotypes of a trait in a population.
Considering your definitions only, then multiple allelism has to do with genetics while polymorphism has to do with the phenotype.
Most loci (=position in the genome) that contain more than one allele (=genetic variant) have no effect on the phenotype. So multiple allelism does not necessarily yield to phenotypic polymorphism.
On the other hand, plenty of phenotypic variation in a population is due to environmental variation (including what an individual eats) and not to genetic variation. So phenotypic polymorphism is not necessarily caused by a case of multiple allelism.
The term polymorphism is broad and can have different meanings. Here are your definitions
Multiple Allelism: The existence of more than two alleles of the same gene within a population.
Polymorphism: the occurrence of more than two distinct phenotypes of a trait in a population.
Considering your definitions only, then multiple allelism has to do with genetics while polymorphism has to do with the phenotype.
Most loci (=position in the genome) that contain more than one allele (=genetic variant) have no effect on the phenotype. So multiple allelism does not necessarily yield to phenotypic polymorphism.
On the other hand, plenty of phenotypic variation in a population is due to environmental variation (including what an individual eats) and not to genetic variation. So phenotypic polymorphism is not necessarily caused by a case of multiple allelism.
This answer refers to polymorphism within genetics (for clarification), which as far as I know is the more common use of the term (but that could just be because I'm a geneticist).
Polymorphism in general refers to genetic variation of traits within a population (or species), due to mutations.
A 'single nucleotide polymorphism' is a single change in the DNA sequence of an organism at some point. So:
A -> Cor
T -> GOr some other combination of these. It is simply a change of a single nucleotide. More specifically, a SNP is present in at least 1% of a given population.
As these mutations (and other types of mutations) accumulate it results in multiple allele variants of a gene.
Here is a good reference: http://www.nature.com/scitable/search-scitable?criteria=Polymorphism
You are right to say that not all alleles will yield a different phenotype.
Finally, in principle, genes do not necessarily have to have more than one allele, it is the result of mutations that cause this.
This answer refers to polymorphism within genetics (for clarification), which as far as I know is the more common use of the term (but that could just be because I'm a geneticist).
Polymorphism in general refers to genetic variation of traits within a population (or species), due to mutations.
A 'single nucleotide polymorphism' is a single change in the DNA sequence of an organism at some point. So:
A -> Cor
T -> GOr some other combination of these. It is simply a change of a single nucleotide. More specifically, a SNP is present in at least 1% of a given population.
As these mutations (and other types of mutations) accumulate it results in multiple allele variants of a gene.
Here is a good reference: http://www.nature.com/scitable/search-scitable?criteria=Polymorphism
You are right to say that not all alleles will yield a different phenotype.
Finally, in principle, genes do not necessarily have to have more than one allele, it is the result of mutations that cause this.
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That is correct. Due to codon degeneracy.. ie one amino acid can be encoded by more than one set of 3 DNA base pairs... you can a difference in DNA but no difference in the protein. This synonymous base changes leads to no phenotype.
Also it is possible for an amino acid change to occur in a protein and cause no phenotype either, as the change may occur in a region that has no over effect on the protein function, folding and interaction with other proteins.
So as you have eluded too, not all allelic variation leads to a phenotypic variation.
That is correct. Due to codon degeneracy.. ie one amino acid can be encoded by more than one set of 3 DNA base pairs... you can a difference in DNA but no difference in the protein. This synonymous base changes leads to no phenotype.
Also it is possible for an amino acid change to occur in a protein and cause no phenotype either, as the change may occur in a region that has no over effect on the protein function, folding and interaction with other proteins.
So as you have eluded too, not all allelic variation leads to a phenotypic variation.
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Is a slightly difference:
polymorphism is a variation in an allele at the sequence level. A common one is Single Mutation Polymorphisms SNPs.
Multiple allelism means that in a population there are more than one alleles for a certain gene.
Is a slightly difference:
polymorphism is a variation in an allele at the sequence level. A common one is Single Mutation Polymorphisms SNPs.
Multiple allelism means that in a population there are more than one alleles for a certain gene.
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The term polymorphism is broad and can have different meanings. Here are your definitions
Considering your definitions only, then multiple allelism has to do with genetics while polymorphism has to do with the phenotype.
Most loci (=position in the genome) that contain more than one allele (=genetic variant) have no effect on the phenotype. So multiple allelism does not necessarily yield to phenotypic polymorphism.
On the other hand, plenty of phenotypic variation in a population is due to environmental variation (including what an individual eats) and not to genetic variation. So phenotypic polymorphism is not necessarily caused by a case of multiple allelism.
The term polymorphism is broad and can have different meanings. Here are your definitions
Considering your definitions only, then multiple allelism has to do with genetics while polymorphism has to do with the phenotype.
Most loci (=position in the genome) that contain more than one allele (=genetic variant) have no effect on the phenotype. So multiple allelism does not necessarily yield to phenotypic polymorphism.
On the other hand, plenty of phenotypic variation in a population is due to environmental variation (including what an individual eats) and not to genetic variation. So phenotypic polymorphism is not necessarily caused by a case of multiple allelism.
More
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