A) Consider the following chromosomes and if they are affected by hemophilia. X = unaffected X chromosome, x = X chromosome affected by hemophilia, and Y = Y chromosome. If an Xx female and XY male have children, what fraction of their offspring will have an affected chromosome, and what fraction is likely to be affected by hemophilia? (1 point)

Question

1/2 and 1/3
1/4 and 1/4
1/4 and 1/2
1/2 and 1/4

Answer 1

To analyze the genetic situation, let's determine the potential genotypes of the offspring produced by an Xx female (carrier of hemophilia) and an XY male (unaffected).

1. The possible gametes from the Xx female are:

   • X (unaffected)
   • x (affected)

2. The gametes from the XY male are:

   • X (unaffected)
   • Y (male)

Combining these, we can set up a Punnett square:

| | X (from male) | Y (from male) | |--------|----------------|----------------| | X (from female) | XX | XY | | x (from female) | Xx | xY |

From this Punnett square, we have the following possible offspring genotypes:

1. XX (unaffected female)
2. XY (unaffected male)
3. Xx (carrier female, not affected)
4. xY (affected male)

Now we can summarize the genotypes of the offspring:

• 1 XX (unaffected female)
• 1 XY (unaffected male)
• 1 Xx (carrier female, not affected)
• 1 xY (affected male)

Now to find the fractions:

• Out of a total of 4 possible offspring:
  • The fraction with at least one affected chromosome (either Xx female or xY male) is 2 out of 4, or 1/2.
  • The fraction likely to be affected by hemophilia (only the xY male) is 1 out of 4, or 1/4.

Therefore, the answer to the question is: 1/2 and 1/4.