Answer:
Punnett square is a tool used to predict the probability of offspring inheriting certain traits based on the parents' genotypes. When it comes to sex-linked traits, such as hemophilia, the inheritance pattern is different from other traits. Hemophilia is caused by a mutation on the X chromosome and is therefore a sex-linked recessive trait.
To create a Punnett square for a sex-linked trait like hemophilia, the following steps can be taken:
Determine the genotypes of the parents: In humans, females have two X chromosomes (XX), and males have one X and one Y chromosome (XY). For example, if the mother is a carrier for hemophilia (XH Xh) and the father does not have hemophilia (XY), their genotypes would be XH Xh and XY, respectively.
Write the parents' gametes: Gametes are sex cells that carry half the genetic information of the parent. The mother's gametes would be XH and Xh, and the father's gametes would be X and Y.
Create the Punnett square: In a typical Punnett square, you would place the possible gametes of one parent along the top and the other parent along the side. However, since hemophilia is a sex-linked trait, you only need to place the mother's gametes along the top of the square, and the father's sex chromosomes along the side.
XH Xh
Y XY XHY XhY
X XHX XhX XX
Determine the possible offspring: Once the Punnett square is completed, you can determine the possible offspring's genotype and phenotype. In the case of hemophilia, males only need one copy of the X-linked gene to express the trait. Therefore, any male offspring with an Xh allele will have hemophilia, while females need two copies of the X-linked gene to express the trait. Females with one Xh allele are carriers and do not show symptoms.
By following these steps, you can use the Punnett square to predict the probability of offspring inheriting hemophilia.
Step-by-step explanation: