Question

Which of the following is a typical characteristic of human traits that follow an X-linked recessive inheritance pattern?

Group of answer choices

more males than females are affected

more females than males are affected

it is passed from father to all sons

affected sons must have an affected mother

Answer 1

Answer-

According to the given question-

• X-linked recessive inheritance – is defined as a mode of inheritance, where the mutation in a gene found on the X chromosome, responsible for causing the change in phenotype and mostly expressed in males (homozygous), because a male has one X and one Y chromosome while females have two X chromosomes, so one copy of mutated gene found in female, be a carrier.
• So In males, one copy of the mutated gene is sufficient for causing the abnormal conditions. But in females, when a mutation occurs in both copies of the gene, then they will be affected with the disorder due to the mutated gene.
• So the females are affected unlikely because they need two copies of the genes, while the males are generally affected, due to X-linked recessive disorder more compared to the females.
• Thus the characteristic that is X-linked does not pass from fathers to their son i.e. no male to male transmission occur. e.g. hemophilia, and Fabry disease. but if the mother is a carrier (having one copy of the gene), then there are 50 % of their sons are affected, but if the mother is affected (Having both copies of the mutated gene) then 100 % of their sons are affected.

thus the correct answer is both- option (a) more males than females are affected and option (d) affected sons must have an affected mother.