how mixed race people have a skin tone that is in between their parents’ skin tone, if Mendel’s law of dominance is true?
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Mendel used his observation of specific physical traits (aka phenotypes) of pea plants as a basis for developing his law. He correctly developed the pundit square and law of dominance through these observations, but that doesn’t mean all physical traits are “mendelian.”
We have access to the source code of life now, DNA. We can identify when phenotypes (physical characteristics) are controlled by single or multiple genes, and through large studies of heritable traits (and disease), determine that not all genes have “complete penetrance.” So even if a gene it’s directly responsible for a trait, that gene does not always result in that trait in offspring.
TLDR; Mendel made amazing leaps in logic with very limited data, but not all physical traits are inherited in simple mendelian fashion, skin tone and eye color are two such traits in humans.
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