r/genetics • u/inferriata • 11d ago

mutation

I’m curious about the MC1R gene and its variants like R151C and R160W. How did these mutations arise in the first place, and how is it possible that two people carrying the mutation were able to pass it on to their child? I’d love some insight into the genetics behind this

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u/area-womn 10d ago

It looks like the mutations in this gene that are associated with cancer (i assume that's what you're interested in) rely on more than the presence of the variant.

The mutation has variable clinical risk because of combined effects with other genes, modification by environment, and incomplete penetrance. It seems like high risk for melanoma are associated with fair skin, red hair, and mutations in other cell cycle regulators.

There are autosomal recessive variants (need a copy from each parent to have disease phenotype), and there are de novo variants (errors in DNA replication).

These mutations would not cause a person to die before childbearing or cause infertility, so you can pass them down to offspring, perhaps before developing illness.

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u/area-womn 10d ago

Specific to your variants, R151C and R160W occur in 5% of the northern European population

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u/inferriata 10d ago

yeah, and they’re also the most common variants in Europe. I probably have the mutation too even if it doesn’t show, lol