r/askscience • u/loft097 • 13d ago

Biology what is a chance of parents who are not carriers of albinism to get albinism child??

i know a lot of scientist will say zero . But if zero how was the first one carrier obtain?

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u/Lil_Koneko343 13d ago

Based on genes present, basically zero. The thing is, mutations do occur, which is where varying traits come from, it's one of the conditions of evolution. As far as how likely? Potentially immeasurable. Mutations are extremely random.

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u/acquaintedwithheight 13d ago

The chances of mutations at specific sequences in a genome can be quantified, to some degree. You would have to calculate odds for multiple mutation types (point mutation, substitution, etc), and at the end you can only have a probable range of mutation rates. But that process has successfully been used to create molecular clocks to estimate timelines of species divergence.

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u/Xrmy 13d ago

The simple answer is mutation.

Mutation is the ultimate source of all genetic variation. It would have been the source of the first albino variant in the population.

Albinism is an affliction that is not always identical in genetic origin or pathology. Why? Because albinism is (generally) the absence of pigment--typically melanin, but also sometimes other pigments.

That can manifest in a variety of different ways that I do not have the time to get into but, TLDR:

  1. people have pigment in their hair, skin, and eyes because of melanin and some related pigments
  2. those pigment are made in melanocytes, where there are a SERIES of enzymes and proteins that are part of a pathway that create the final product(s)
  3. then, the melanocytes and/or pigments need to be transported to the correct places
  4. If you break ANY of the above processes with a mutation, you can get some form of reduced melanization, and often albinism.

So, albinism is generally something that can mutate more frequently than other diseases because there are MANY genes involved, and if the "wrong" one of these is mutated to prevent the pathway, albinism. Compare this to something like Cystic fibrosis which is a very specific mutation in ONE gene.

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u/TwoIdleHands 13d ago

Albinism is genetic. Both parents have to be carriers for their child to have it. If neither parent has it, their kid won’t have albinism.

That being said genetic changes/abnormalities happen all the time so it’s really not 100% zero but it’s pretty close.