So… if you are a boy, then you have XY and you got your X from mom and your Y from dad.

If you are a girl, then you are XX and you got one X from mom and one X from dad.

Hope that helps!!!

Generally speaking, you have two genes for each of your body traits. If they code for different specifics (say, blue eyes vs. brown eyes), the one that is expressed is the dominant gene and the one which is not is the recessive. “Defective” genes are almost always recessive – a dominant defective is almost a contradiction in terms. Color-blindness, for instance, is the result of defective genes. That’s one of the cases where women are at something of an advantage. The Y chromosome is shorter, containing less genetic information than the X chromosome. Consequently, if the gene for something is in the X chromosome but not in the Y, men are more likely to have a defective gene expressed. Color-blindness is such a case: with two X-chromosomes, a woman would have to have a defective gene in both of them to be red/green color blind. A man has the gene only in his single X chromosome, so if that one’s defective, he’s out of luck. This is why most color-blind people are men. There are color-blind women, but they’re much less common.

As regards your particular experiment, all I can say is to check the lab background. There must be a gene like the color-blindness one that the experiment tests for.

Wish I could be more help.