If a normal man marries a normal woman whose father was colourblind, what are the chances that their sons and daughters will be colourblind? Colourblindness is a sex-linked trait that affects males more often than females. With the aid of a Punnett square, indicate the genotypes of the parents, and of the offspring, including their chances of being colourblind in the F1 generation.

If woman's father was colorblind, and she was not, she will be a carrier. One of her X chromosomes will have the recessive colorblind gene.

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To determine the chances of their sons and daughters being colorblind, we need to understand the genetics of colorblindness. Colorblindness is a sex-linked trait, which means it is located on the sex chromosomes (X and Y). The gene for color vision is found on the X chromosome.

To answer this question, we need to know the genotypes of the parents—specifically, whether the normal woman is a carrier of the colorblindness gene. Since her father was colorblind, we can assume that she carries one normal gene (X^N) and one colorblind gene (X^C). For simplicity, let's use "N" to represent normal vision and "C" for colorblindness.

The father, as a normal man, has an XY genotype since he only has one X chromosome.

Now let's create a Punnett square to determine the genotypes and phenotypes of their offspring:

X^N X^C
------------
Y | X^N X^CY
------------

The Punnett square shows four possible combinations in the offspring.

Genotypes:
- 50% chance of sons being normal (X^NY)
- 50% chance of daughters being carriers (X^NX^C)

Phenotypes:
- All sons will be non-colorblind because the Y chromosome does not carry the colorblindness gene.
- 50% of daughters will be carriers (non-colorblind) because they have one normal X chromosome (X^N) and one colorblind X chromosome (X^C).

To summarize, in the F1 generation, all sons will have normal color vision, while 50% of daughters will have normal color vision and the other 50% will be carriers of colorblindness.

Remember that these are the theoretical probabilities based on the Punnett square, and actual results may vary.