Question

in the following pedigree, is the disorder's mode of inheritance autosomal dominant autosomal recessive, or X-linked recessive? Explain your reasoning

Answer 1

In pedigrees the trai of interest is shown in color, meanwhile, sex is represented in squares and circles, so we can see that those that present the trait of interest are circles and squares so we can discard a sex-linked trait either be in chromosome X or Y, now if we look carefully at the color, we can see as long as the color is present the offspring will have also at least 1 color, meanwhile, in the only couple in white the offspring has no color either, this indicates us that this is an autosomal dominant trait.