Question

the figure shows the pedigree of a family. dark - shaded symbols represent individuals with one of the two major types of colon cancer. numbers under the symbols are the individuals age at the time of diagnosis. males are represented by squares, females by circles. based on this pedigree, this trait is most likely inherited ____. as a recessive trait as a result of epistasis as a dominant trait by older individuals

Explanation:

• Recessive trait: If it were recessive, we would expect more cases where unaffected parents have affected children (like two unaffected parents having an affected child). But here, we see affected individuals having affected offspring in a pattern more consistent with dominant.
• Epistasis: Epistasis is about interaction of genes, not directly shown in this simple pedigree pattern.
• Dominant trait: In a dominant trait, an affected individual (heterozygous or homozygous dominant) can pass the trait to offspring. We see multiple generations with affected individuals, and an affected parent (like in generation II - 3) having affected children (generation III - 4 and IV - 1).
• By older individuals: Age at diagnosis is just a data point. The inheritance pattern (affected parents having affected children) is more indicative of dominance than age - related acquisition.

Answer:

as a dominant trait