What is a characteristic pattern of inheritance for hemophilia?

Hemophilia is a genetic disorder that impairs the body's ability to make blood clots, a process essential for stopping bleeding. The characteristic pattern of inheritance for hemophilia is X-linked recessive. This means that the gene associated with hemophilia is located on the X chromosome and that the disorder primarily affects males, who have one X and one Y chromosome. Males are more likely to express the condition since they only need one copy of the mutated gene.

Females, on the other hand, have two X chromosomes, so they can be carriers of the hemophilia gene without showing symptoms if they have one normal and one mutated gene. If a female does inherit two copies of the hemophilia gene, she will express the condition, but this is less common. As a result, males are more frequently affected by hemophilia, showcasing the uniqueness of X-linked inheritance patterns where males present the disorder and females may be carriers.

This inheritance pattern explains why hemophilia tends to run in families, especially affecting males, and outlines a crucial concept in genetics regarding how X-linked traits are passed from parents to offspring.