Chapter 1: The Cellular Powerhouse

At a lively children's birthday celebration, amidst leftover pizza and melting ice cream, I engage in conversation with a fellow MIT alumna. She’s delving into a project focused on the origins of plant mitochondria—those minute organelles found in most eukaryotes, often invisible unless specifically stained.

Mitochondria were first identified and named in the 19th century, and their intricate workings have led numerous scientists to receive the Nobel Prize in Chemistry during the 20th century. The primary role of mitochondria is to produce glucose and oxygen through aerobic respiration, generating energy for cells in the form of adenosine triphosphate (ATP), while also managing cell metabolism and growth.

Interestingly, mitochondria and their dynamic networks were not part of the original eukaryotic governing structures. The discovery of a distinct mitochondrial genome, separate from nuclear DNA, provided substantial backing for the endosymbiotic theory regarding their origin. This theory suggests that an ancient free-living prokaryote entered a eukaryotic cell, adapted to coexist, and eventually became integrated into the cell's overall physiology through an endomembrane system. This evolution resulted in the modern mitochondrion, which constantly undergoes fission and fusion to assist its eukaryotic host in converting oxygen into chemical energy. This adaptation offered a significant evolutionary advantage compared to previous anaerobic fermentation processes.

Mitochondria replicate and divide based on the ATP requirements of cells. They are crucial for metabolic functions, including hormonal signaling, immune responses, calcium signaling, and detoxifying waste products through enzyme activity. They also possess the capability to repair oxidative DNA damage caused by reactive free radicals through various mechanisms. However, persistent oxidative stress can diminish mitochondrial function, increase abnormal enzyme activities, and accelerate aging.

A unique characteristic of mitochondria is that they are inherited solely from the mother. Research into the variations and mutations of individual mitochondrial DNA has provided insights into evolutionary biology. This is how scientists identified "Mitochondrial Eve," the most recent common matrilineal ancestor of modern humans, believed to have originated from continental Africa.

This mitochondrial genome serves as a living testament to an unbroken matrilineal lineage, passed down uninterrupted from mothers to daughters. Reflecting on this, I feel both awe and gratitude. Since the time of early ancestors like Lucy, at least one daughter in each generation has carried this invisible cellular powerhouse, connecting me to my daughters even after hundreds of thousands of years.

Recently, I embarked on a project to uncover the "forgotten history" of my female ancestors. While I could name my great-grandmothers, no one in my immediate family could identify the women who came before them. The tradition of adopting the husband's surname and using "Mrs." has obscured the names of my great-great-grandmothers from the memories of those I consulted.

Perhaps there are clues hidden in dusty family records. On my father's side, I know an uncle possesses our family's "genealogical scroll," a grand document filled with neatly written names spanning about twenty generations. Unfortunately, the names of female spouses were recorded only as "Mrs. Maiden-Name Husband's-Surname." It’s fortunate these women were acknowledged at all, as none of the daughters in each generation were included.

This selective history reflects what Kate Manne describes in her book "Down Girl" (2017) as Herasure: a systematic exclusion of women from the narrative of family history.

Since my paternal grandparents' passing, and the loss of my eldest aunt shortly thereafter, the family scroll has been tucked away, either in a safety deposit box or a forgotten corner. I often wonder if my father's generation will continue the tradition of documenting their kin as they pass on.

Yet, how could they reconcile the absence of their eldest sister, the most accomplished among them, who tragically succumbed to glioblastoma, from this family legacy? Perhaps it’s time to break away from tradition.

For a long while, I have identified more closely with my father's family, drawn to their privilege and status. However, in this conversation with my fellow mom, a desire stirs within me to learn more about my maternal lineage and the women who lived more ordinary lives—whose mitochondria are also a part of me.

Which of these women do I resemble the most? What stories do they hold?

Modern research highlights how the balance, or lack thereof, between mitochondrial fission and fusion is crucial to understanding certain diseases. Mitochondrial dysfunction can lead to systemic or neurological disorders, such as autism, diabetes, and infertility in both genders. Genetic predispositions can be exacerbated by environmental factors, which may trigger diseases rooted in mitochondrial dysfunction. Recent studies have even explored how cancer cells can outmaneuver the mitochondria of immune cells.

Mitochondria are key to understanding our narratives. This remarkable organelle is vital not only for my health and that of my family but also calls for deeper, more nuanced investigations into women's health. The implications extend to the well-being and advancement of humanity as a whole. The exploration of this field is captivating, and we are merely beginning to uncover the roles these organelles play in the narratives of our lives and in women's history.

Chapter 2: The Scientific Exploration of Mitochondria

This video titled "Is the Mitochondria Always the Powerhouse of the Cell?" delves into the complexities of mitochondrial function and its significance in cellular biology. It provides insights into how these organelles contribute to energy production and overall cell health.