Skin colour is determined by melanin presence. Skin colour is a polygenic inheritance. It involves multiple genes in order to have a phenotypic expression (the colour we see). You do not see the genotypic expression.
If order to determine what colour (phenotype) your grandkids would be, you need to know the exact genotype (skin colour trait) of each individual, that will give you a probability of the skin type of the grandkids. Skin colour is also influenced by environmental factors.
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Skin colour is determined by melanin presence. Skin colour is a polygenic inheritance. It involves multiple genes in order to have a phenotypic expression (the colour we see). You do not see the genotypic expression.
If order to determine what colour (phenotype) your grandkids would be, you need to know the exact genotype (skin colour trait) of each individual, that will give you a probability of the skin type of the grandkids. Skin colour is also influenced by environmental factors.
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Hope this will help you