What are dominant allele masks?

A dominant allele mask is like a superhero costume that hides what’s underneath, even if something else is trying to show through.

Imagine you have two types of crayons: red and blue. Each color represents an allele, which is like a version of a gene. If the red crayon is the dominant allele, it gets to be the one on top, covering up the blue crayon, even if both are used to draw a picture.

Now think about your socks. Let’s say you have two socks: one is a dominant allele (let's say it’s red), and the other is a recessive allele (blue). When you put them on, the red sock shows through, it masks the blue one. That’s how a dominant allele mask works in real life.

It’s like having two rulers on your desk, one short and one long. If you use the long ruler (the dominant allele), that's what people see, even though the short one is there too. The long ruler masks the short one, just like how a dominant allele hides the recessive one.