Could anyone clearly answer me how does a lethal gene work?

These are genes found in an organism's genome that result in the death of the carrier organism. Occasionally, a mutation happens in a gene responsible for the specific organism's growth and development. These mutations can be dominant or recessive, and they can cause the organism to die before or at any point after, but most of the time, if the organism doesn't die at birth, it dies soon after.

A lethal gene is a gene that, when present in certain combinations or conditions, causes death of the organism carrying it. This can occur through various mechanisms such as disrupting essential biological processes or causing severe developmental abnormalities. In some cases, lethal genes may be recessive and only cause death when inherited from both parents, while in other cases, they may be dominant and cause death even when inherited from just one parent.