Reference no: EM131135482

Sex linked traits can be a little confusing because you now have more than 2 possible alleles. You have both the chromosome for gender and the allele for the colorblind trait so you have XN (normal), Xn (colorblind), and Y. The Y chromosome doesn't have an area for a gene for color vision, so the colorblind trait can only be inherited from the X chromosome.
So consider what the phenotypes (how the gene is expressed) for the possible combinations:

XN XN (female, normal color vision)
XN Xn (female with normal color vision, but carries the allele for colorblindness)
Xn Xn (female, colorblind)
XN Y (male, normal vision)
Xn Y (male, colorblind)

There's no way to have a male "carrier", he would either be colorblind or have normal vision because he only gets one allele that affects color vision.

To apply this to your problems:

1. What is the genotype of a male with red-green color blindness?
2. What is the genotype of a female who is not color-blind but is a carrier of red-green color blindness?
3. Even though red-green color blindness is a recessive trait, can a female have red-green color blindness? Explain.
4. A man who is color-blind marries a woman who is not color-blind and is not a carrier of the allele for color blindness. Create a Punnett square to predict the possible genotypes of their children.
5. Will all of the female children be carriers of the color-blind allele, or will none be carriers? Explain.
6. Will all of the male children be color-blind, or will none be color-blind? Explain.