Whats the Difference between Autosomal Dominant and Autosomal Recessive?
Autosomal Dominant genes express themselves when present. Autosomal Recessive genes will only express themselves when in the homozygous state — i.e., both genes in the gene pair are the recessive gene form. Thus, recessive genes can be “carried” by those whose phenotype does not exhibit the gene characteristic, while dominant genes cannot be “carried”. According to Mosby’s Medical & Nursing Dictionary, autosomal-dominant inheritance is “a pattern of inheritance in which the transmission of a dominant gene on an autosome causes a characteristic to be manifested. Males and females are affected with equal frequency. Affected individuals have an affected parent (unless the condition is the result of a fresh mutation). Half of the children of a heterozygous affected parent are affected. All of the children of a homozygous affected parent are affected. Normal children of an affected parent do not carry the trait.” In comparison, Mosby’s defines autosomal-recessive inheritance as “a pattern