Final answer:
Pedigree analysis reveals that X-linked recessive disorders occur more frequently in males due to their single X chromosome. Affected fathers can only pass the X-linked recessive allele to their daughters, making them carriers, but cannot affect their sons. Carrier mothers have a 50% chance of having affected sons and daughters that are carriers.
Step-by-step explanation:
Pedigree analysis on a characteristic shows that certain patterns emerge when dealing with X-linked recessive disorders. In the context of human genetics, a key observation is that females (F) are affected less frequently than males. This is due to the fact that males have only one X chromosome; therefore, a single recessive allele on the X chromosome results in the male being affected by the disorder. An affected father may pass on the allele to his daughters, making them carriers if the mother is unaffected, but since he provides a Y chromosome to his sons, they will not be affected. As for the mothers, if they are carriers of the recessive allele, there is a 50% chance that their children will be affected. Specifically, their sons have a 50% chance of being affected, while their daughters will have a 50% chance of being carriers, not affected, unless they inherit another recessive allele from their father.
It's evident through this analysis that with X-linked recessive diseases, males are more likely to be affected because they have just one X chromosome. On the other hand, females can carry the disease without being affected if they have only one recessive allele, which is masked by a dominant allele on the second X chromosome. Consequently, this results in a scenario where affected males cannot pass the disorder to their sons, but all daughters will be carriers if the mother is unaffected, and some daughters will be affected if the mother is also a carrier or affected.
The pattern where half the children of affected mothers are affected applies when the mother is a carrier of the given X-linked recessive disorder. Both sons and daughters have an equal chance of inheriting the allele, but the expression of the disorder will differ with the sex of the offspring due to the presence of one or two X chromosomes.