Explain how the results exclude the possibility that the trait is encoded by a mitochondrial gene.

Mitochondrial gene is the gene which inherited from mother tothe offspring.

Explanation:

Some portion of DNA is also present in the mitochondria of the cell so mitochondrial gene is also transmitted from parent to their offspring. In humans, mitochondrial gene is transmitted from only one parent i. e. mother not father. The mitochondrial disease occurs in the human if the disease is present in the mother because it is transferred through genes from mother to their offspring. There are variety of diseases that occurs due to mitochondrial gene such as Mitochondrial myopathy, Diabetes mellitus and deafness etc. So the mitochondrial gene plays a vital role in the structure and function of human body.