In humans, hemophilia is a sex linked trait. Females can be normal, carriers, or have the disease. Males will either have the disease or not (but they won’t ever be carriers) X”X’ x”Y = female, normal = male, normal X”X” x” Y = female, carrier male, hemophiliac x” x” X X = female, hemophiliac
The Correct Answer and Explanation is :
The given genetic cross describes the inheritance of hemophilia, a sex-linked recessive disorder, which is carried on the X chromosome. In this case, the different symbols represent individuals’ genotypes based on their sex chromosomes, where “X” refers to a normal X chromosome and “X'” represents the hemophilia allele on the X chromosome. Here’s the breakdown of the cross:
Parental Genotypes:
- Female (X”X’) = A carrier of the hemophilia allele. She has one normal X chromosome (X) and one hemophilic X chromosome (X’).
- Male (X”Y) = A normal male, as males have one X and one Y chromosome, and the X chromosome is normal (X”).
Punnett Square:
For the cross X”X’ x X”Y, we need to determine the possible offspring:
| X” (Mother) | X’ (Mother) | |
|---|---|---|
| X” (Father) | X”X” (female, normal) | X”X’ (female, carrier) |
| Y (Father) | X”Y (male, normal) | X’Y (male, hemophiliac) |
Explanation:
- X”X” (female, normal): This female inherits a normal X from both parents, so she is not affected by hemophilia.
- X”X’ (female, carrier): This female inherits a normal X chromosome from her father and a hemophilic X from her mother, making her a carrier of the disorder but not affected by it.
- X”Y (male, normal): This male inherits the normal X chromosome from his mother and the Y chromosome from his father, so he is not affected by hemophilia.
- X’Y (male, hemophiliac): This male inherits the hemophilic X chromosome from his mother and the Y chromosome from his father, so he has hemophilia.
Key Points:
- Hemophilia is a recessive trait on the X chromosome, which means males with the hemophilia allele on their only X chromosome will be affected.
- Females need two copies of the hemophilia allele (one on each X chromosome) to be affected by the disease, making them more likely to be carriers if they inherit only one allele.
Now, I’ll generate the image for this Punnett square.
Here is the generated image of the Punnett square showing the inheritance of hemophilia. It details the genetic cross between a carrier female (X”X’) and a normal male (X”Y), along with the possible outcomes for their offspring. Let me know if you need further explanation or adjustments!
