A year or so ago my sister took a dna test. Some other family members have also taken the test. The results showed an inconsistency in mitochondrial dna. My sis

A year or so ago my sister took a dna test. Some other family members have also taken the test. The results showed an inconsistency in mitochondrial dna. My sister had a different kind than our cousins. When she first found out she could only find 2 explanations. A super rare, basically impossible, random mutation or my sister and cousins had different female ancestors. My sister hoped for number 2. She imagined our grandpa having an affair that resulted in our mom. To avoid shame our grandma raised the love-child as her own. my sister and I have always felt out of place so this would certainly explain everything. Turns out the dna test is just not great at distinguishing mitochondrial dna.