Maternal Mitochondria
Did you know all mitochondrial DNA comes only from your mother?
As a fan of Bod•ē TEN, you already know how important mitochondria are to every facet of your body. However, do you know where your mitochondria come from? As it turns out, you get your mitochondria from your mother! “Our mitochondrial DNA accounts for a small portion of our total DNA. It contains just 37 of the 20,000 to 25,000 protein-coding genes in our body. But it is notably distinct from DNA in the nucleus. Unlike nuclear DNA, which comes from both parents, mitochondrial DNA comes only from the mother.” Essentially, paternal mitochondria are present in the earliest stages of embryonic development, but there is a sort of self-destruct mechanism that erases it. In one study with ringworms, scientists discovered that if they intervened and delayed this process, the result was higher death rates for the embryos.
“It’s well known that the transfer of mitochondrial DNA from mother to offspring, often called maternal inheritance, occurs in humans and most multicellular organisms. Maternal inheritance is what allows genetic testing services to trace our maternal ancestries. You inherited your mitochondrial DNA from your mother, who inherited hers from her mother and so forth. Maternal inheritance also gave rise to the idea that there exists a ‘Mitochondrial Eve,’ a woman from whom all living humans inherited their mitochondrial DNA.” But why is it that maternal mitochondria make the grade and paternal mitochondria do not? The short answer is that we do not yet know why. “One theory has to do with the fact that sperm must generate a lot of energy when competing to fertilize an egg. During this time, sperm mitochondria are overworked, which could possibly damage their DNA and lead to mutations.”[1] However, further studies need to be completed in order to confirm whether or not this theory has any merit.
[1] Yin, Steph. “Why Do We Inherit Mitochondrial DNA Only From Our Mothers?” The New York Times, The New York Times, 23 June 2016, www.nytimes.com/2016/06/24/science/mitochondrial-dna-mothers.html.