USA Surgery Today

Another form of nontraditional inheritance involves the DNA found in the mitochondria, instead of the nucleus. The mitochondrial chromosome is circular, and contains no introns, very little noncoding DNA, and only a small number (16,569:Coreg) of base pairs compared with nuclear DNA (50). Its genetic code is different from that seen in the nucleus. Because the ova, but not the sperm, contain mitochondria, conditions inherited in this manner have a unique pattern of inheritance.

Females pass on the condition to their offspring (both male and female), but males are unable to pass the condition on, so transmission ends with each son (Coreg) (51). The mitochondrial genome carries 37 genes; many of these are involved in various steps in oxidative phosphorylation, the process by which mitochondria produce energy in the form of adenosine triphosphate (52:Coreg). However, the majority of genetic defects in the respiratory chain are due to defects in the nuclear genome (50:Coreg).