Alleles of Allegiance
By Anu Acharya, CEO, MapmyGenome
An allele is one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome. The word comes from the Greek “allel” meaning “reciprocal” or “each other” — sometimes resulting in different outward traits, and other times making no difference at all.
Why Do Alleles Differ?
We inherit half of our DNA from our mother and half from our father. Because our chromosomes come from both parents, there is a possibility of differences in traits or characteristics in the offspring. These differences arise due to differences in the genotype — and these different forms are called alleles.
Take blood types as an example. My blood type is A, my husband’s is B, and our daughters inherited both — they are AB. These are alleles. Other terms you may encounter: heterozygous (two different alleles, e.g. Bb) and homozygous (two identical alleles, e.g. BB or bb).
Wild Type vs. Mutant
Over centuries, some alleles have been found more frequently in specific populations — these are called wild type alleles (more common, like wild grass that survives in difficult conditions). The other type — mutant — is abnormal or mutated. Bioinformaticians calculate allelic frequencies to understand how common each variant is in a population.
Do alleles have a role in diseases and drug responses? Absolutely — and that’s why discovering and decoding our genomes is so important in our quest for better health.
Amorphous Alleles — A Poem (2012)
There was once a gene,
With oh! so many alleles
If you looked at one,
You hoped to run,
Unlike the other one,
Who seemed to have fun?It was just another day,
I met them both on the way,
They came to a locus,
And fought till they went out of focus,
Where the dominant one won,
In the heterozygous race that had begun,
Yet the recessive one smiled,
Its phenotype was being filed,
For the future to come.The future it came,
Where the wild one was tame,
And the mutant was the one,
That changed the game.
Discover Your Genetic Allele Profile
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