Polygenic inheritance and multiple alleles

[Nialllovespie]

Hiya,

Could someone please explain the difference between polygenic inheritance and multiple alleles?

I'm really confused )

Nia

[Quantum44]

Polygenic inheritance is where multiple genes contribute to the expression of one phenotype.
Alleles are variations of genes.

They are two different concepts. A gene can have multiple alleles while a phenotype can be controlled by multiple genes.

[anonymous99]

Hiya,

Could someone please explain the difference between polygenic inheritance and multiple alleles?

I'm really confused )

Nia

Okay think about it this way: Everyone in the world is different right (eye colour, hair colour, height etc.) right? Which means that, while we all have the same GENES (i.e. stuff that codes for eye colour, hair colour, height etc.), we all have DIFFERENT ALLELES (versions of those genes). That's basically what multiple alleles means- it means that in a population, you have just a bunch of different versions of genes, and you can create different combinations/ genotypes (and eventually phenotypes) in them.
BUT
Polygenic inheritance is a different concept. This is where you've basically got one trait (we'll say height). Now, everyone's height is different. From before, we deduce there must be different alleles (Different combinations of alleles gives you different heights). But- the difference between the characteristic of height and the charcateristic of say, eye colour is that your eye colour is only determined by 2 alleles, whereas height is determined by MULTIPLE alleles (hence, POLYgenic inheritance). Now, there can be MULTIPLE alleles (possible in a population) for BOTH characterisitcs...but ONLY HEIGHT is CODED by MULTIPLE ALLELES (eye colour is coded by ONLY TWO alleles).

[vox nihili]

Okay think about it this way: Everyone in the world is different right (eye colour, hair colour, height etc.) right? Which means that, while we all have the same GENES (i.e. stuff that codes for eye colour, hair colour, height etc.), we all have DIFFERENT ALLELES (versions of those genes). That's basically what multiple alleles means- it means that in a population, you have just a bunch of different versions of genes, and you can create different combinations/ genotypes (and eventually phenotypes) in them.
BUT
Polygenic inheritance is a different concept. This is where you've basically got one trait (we'll say height). Now, everyone's height is different. From before, we deduce there must be different alleles (Different combinations of alleles gives you different heights). But- the difference between the characteristic of height and the charcateristic of say, eye colour is that your eye colour is only determined by 2 alleles, whereas height is determined by MULTIPLE alleles (hence, POLYgenic inheritance). Now, there can be MULTIPLE alleles (possible in a population) for BOTH characterisitcs...but ONLY HEIGHT is CODED by MULTIPLE ALLELES (eye colour is coded by ONLY TWO alleles).

Sorry to be THAT person, but none of this is true.

Alleles are different versions of the same gene. So, for instance, you have a gene that codes for beta-globin, a component of the protein in the blood that carries oxygen around (haemoglobin). There can be slight differences in the structures of the beta-globin gene. Each of these differences are called alleles.
Polygenic inheritance doesn't mean that multiple alleles contribute to the trait, but rather, multiple genes. So, for instance, there isn't just one gene for eye colour, nor is there one gene for height. There are multiple genes across multiple chromosomes that each make a contribution to these traits.

[Nialllovespie]

Thanks for your help guys!