Video - Inheritance patterns

Inheritance patterns refer to the different ways in which traits are passed from one generation to another. There are three patterns of inheritance: autosomal dominant, autosomal recessive, and X-linked.

Autosomal dominant inheritance means that only one copy of the defective gene is necessary for the trait to be expressed. This pattern is seen in conditions such as Huntington's disease and Marfan syndrome.

Autosomal recessive inheritance means that two copies of the defective gene are necessary for the trait to be expressed. This pattern is seen in conditions such as cystic fibrosis and sickle cell disease.

X-linked inheritance means that the gene is located on the X chromosome. Males have only one X chromosome, so they will express a disease if it is carried on that chromosome. Females have two X chromosomes, so they will only express a disease if they inherit two defective copies of the gene (one from each parent). This pattern is seen in conditions such as hemophilia and color blindness.