Are skin color, hair color and eye color continuous or discontinuous? Everyone s

Question

Are skin color, hair color and eye color continuous or discontinuous?

Everyone says they're discontinuous, but I dont see how that is the case! All these traits are determined by more than 1 or 2 genes, they're all polygenic traits, and they show a gradation of colors - you don't just have either blue or black eyes, you have brownish black eyes, hazel eyes, slightly darker than hazel eyes, slightly darker than brown eyes etc. etc. you get my point? So why is everyone saying you have "distinct groups of colors like green, blue, brown, black"?

The definition for continuous variation are traits that show variations, and are ALWAYS determined by many genes, and MOST OF THE TIME largely affected by the environment.
The definition for discontinuous variation are traits that show clear cut and distinct groups, and are ALWAYS determined by 1 or 2 genes (a few, but not necessarily 1 gene), and is MOST OF THE TIME not affected by the environment, though there are exceptions.

And clearly hair color, skin color and eye color all fall under the definition of a continuous trait, because even though they dont seem to be affected by the environment, they are definitely polygenic traits and show a gradation, so they're definitely continuous traits. Is that not the case?

Please help! This question has been bugging me since forever and it's confusing me with genetics!

Explanation / Answer

You are exactly correct Eye color , skin color , hair color come under continuous variation.Because the above mentioned characters are not related to discontinuous variation. A variation is nothing but change in the character comparing with the parent.If these characters are discontinuous variation we may find either one or two varieties. But if u consider the eye color like blue or black eyes, brownish black eyes, hazel eyes, slightly darker than hazel eyes, slightly darker than brown eyes etc are there. It means for a single gene there are so many alleles. This concept is called multiple allelesm.It means the individuals are having various types are alleles related to to the same gene responsible for the character eye color. As per the combination of alleles the the phenotype will be confirmed. So as u said all the above characters are under the continuous variations. not under the discontinuous variations.

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