Z0 sex-determination system

Sex-determination is all about determining whether a living being is a boy (male) or a girl (female). In many animals and humans, this is determined by the presence of certain chromosomes that carry genes responsible for sex.

Now, the z0 sex-determination system is a little different. It is a way of determining the sex of certain types of insects, like butterflies and moths.

These insects have a set of chromosomes that are designated as 'Z' and 'W'. If an individual insect has two Z chromosomes, it will be a male. On the other hand, if it has one Z chromosome and one W chromosome, it will be a female.

So basically, the presence of a W chromosome is what determines if an insect is female in this system. It's like a secret code that only certain insects know!