Quote Originally Posted by paulh View Post
In other words, you expect 50% males and 50% females. Of a male-maker's offspring, each male baby has a 25% chance of being normal, a 25% chance of being banana, a 25% chance of being spider, and a 25% chance of being banana spider. Each female baby has an approximately 49% chance of being normal and a 49% chance of being spider. There is a tiny chance of a female banana or female spider banana, but don't expect any.


Biochemically, codominant and incomplete dominant mutants act differently. At the level we are working at, we can't tell the difference. For simplicity, we lump both together under the term "codominant".

If homozygous spider is usually lethal before hatching, then spider is a codominant mutant gene. We call spider a dominant mutant gene because it is not a recessive mutant gene and we are unsure whether it is a full dominant or a codominant (or one of the other types of less than fully dominant mutants).


I am pretty sure that neither the spider nor the banana mutant gene is sexlinked. If banana was sexlinked, a male banana's female offspring would be 50% banana. I don't think anyone has figured out the reason for male-makers and female makers.

I have wondered. If a male-maker banana male is mated to a normal female, are there statistically more males than females? Or are the males and females approximately equal in number?
I like the way you explain things. Although I still don't really understand the last paragraph about sex linked gene.