Mai’s reflection on LUCA feels like a quiet embrace a reminder that we are, at our core, connected in ways far deeper than bloodlines or borders. There’s something profoundly moving in the idea that every breath we take, every heartbeat, carries the echo of a life form that survived a world of fire and chaos billions of years ago. Her words don’t just inform they comfort. They remind us that we are not isolated beings, but part of a vast, ancient story written in molecules and memory. LUCA isn’t just science; it’s belonging. It’s the whisper of unity in a world that often forgets how deeply intertwined we truly are.
As a genetic genealogist, I imagine you're also interested in mitochondria, Mai. As an endurance cyclist, they fascinate me too.
Mitochondria came along after LUCA, but now they live inside the cells of all animals, plants, fungi, and most single-celled organisms with a nucleus (called eukaryotes). Here's what makes them special: while these organisms have their own DNA stored in the cell's nucleus, mitochondria carry separate DNA of their own.
Scientists think that billions of years ago, a larger single-celled organism swallowed a smaller one—but instead of digesting it, the two struck up a partnership. They've been living together, one inside the other, ever since. It's one of evolution's greatest team-ups.
This matters in two fascinating ways:
For genealogy: Because mitochondrial DNA passes directly from mother to child (largely unchanged), genetic genealogists can use it to trace maternal lineages far back in time.
For endurance sports: Mitochondria are like tiny power plants in our cells. When we eat sugars, mitochondria convert them into a form our muscles can use for energy. For distance cyclists and runners, having efficient, abundant mitochondria means being able to keep going for longer. That's why endurance athletes do specific training designed to boost their mitochondrial function—essentially giving themselves more and better cellular power plants to fuel those long rides and runs.
Pretty amazing that something so small plays such a huge role in both understanding our ancient past and powering us through modern challenges!
The big question on “what is Life” is really two questions. Can some ingredients coalesce into a unit that can be considered alive and how is it now differentiated from not-life? Perhaps the “life” aspect can be considered the storage and utilization of (useful) energy, usually involving phosphorus which is not usually available in adequate concentrations in places where people assume life originated. Charging and uncharging the phosphorus compounds to store and release energy introduces something like a respiratory process. So you could have a bit of living material known by its ability to process energy.
But the other major question must be addressed - how did the data storage system develop that keeps track of the living system and coordinates its increasing complexity? How exactly did DNA and RNA come into being, the “Book of Life” as it were - who or what wrote that?
Kathleen, you might be aware of the 'RNA-world' hypothesis [1]. Molecular fossils in contemporary life strongly support that RNA evolved before coded proteins and DNA genomes [2], and recent lab results have produced RNA enzymes that can make accurate copies of other functional RNA strands while also allowing variants to emerge. [3]
That's still only part of the story, though. It's super hard to produce long enough RNA polymers by purely random processes [4] so it's open what form of help they might have had how, and there's still exploration of non-RNA world alternatives.
Mai’s reflection on LUCA feels like a quiet embrace a reminder that we are, at our core, connected in ways far deeper than bloodlines or borders. There’s something profoundly moving in the idea that every breath we take, every heartbeat, carries the echo of a life form that survived a world of fire and chaos billions of years ago. Her words don’t just inform they comfort. They remind us that we are not isolated beings, but part of a vast, ancient story written in molecules and memory. LUCA isn’t just science; it’s belonging. It’s the whisper of unity in a world that often forgets how deeply intertwined we truly are.
Wonderfully written as always Adrião, many thanks 🙏
As a genetic genealogist, I imagine you're also interested in mitochondria, Mai. As an endurance cyclist, they fascinate me too.
Mitochondria came along after LUCA, but now they live inside the cells of all animals, plants, fungi, and most single-celled organisms with a nucleus (called eukaryotes). Here's what makes them special: while these organisms have their own DNA stored in the cell's nucleus, mitochondria carry separate DNA of their own.
Scientists think that billions of years ago, a larger single-celled organism swallowed a smaller one—but instead of digesting it, the two struck up a partnership. They've been living together, one inside the other, ever since. It's one of evolution's greatest team-ups.
This matters in two fascinating ways:
For genealogy: Because mitochondrial DNA passes directly from mother to child (largely unchanged), genetic genealogists can use it to trace maternal lineages far back in time.
For endurance sports: Mitochondria are like tiny power plants in our cells. When we eat sugars, mitochondria convert them into a form our muscles can use for energy. For distance cyclists and runners, having efficient, abundant mitochondria means being able to keep going for longer. That's why endurance athletes do specific training designed to boost their mitochondrial function—essentially giving themselves more and better cellular power plants to fuel those long rides and runs.
Pretty amazing that something so small plays such a huge role in both understanding our ancient past and powering us through modern challenges!
Thank you so much for your input 🙏, it's a fascinating subject.
The big question on “what is Life” is really two questions. Can some ingredients coalesce into a unit that can be considered alive and how is it now differentiated from not-life? Perhaps the “life” aspect can be considered the storage and utilization of (useful) energy, usually involving phosphorus which is not usually available in adequate concentrations in places where people assume life originated. Charging and uncharging the phosphorus compounds to store and release energy introduces something like a respiratory process. So you could have a bit of living material known by its ability to process energy.
But the other major question must be addressed - how did the data storage system develop that keeps track of the living system and coordinates its increasing complexity? How exactly did DNA and RNA come into being, the “Book of Life” as it were - who or what wrote that?
Kathleen, you might be aware of the 'RNA-world' hypothesis [1]. Molecular fossils in contemporary life strongly support that RNA evolved before coded proteins and DNA genomes [2], and recent lab results have produced RNA enzymes that can make accurate copies of other functional RNA strands while also allowing variants to emerge. [3]
That's still only part of the story, though. It's super hard to produce long enough RNA polymers by purely random processes [4] so it's open what form of help they might have had how, and there's still exploration of non-RNA world alternatives.
1. [https://en.wikipedia.org/wiki/RNA_world]
2. [https://pmc.ncbi.nlm.nih.gov/articles/PMC10351881/]
3. [https://phys.org/news/2024-03-life-evidence-rna-world.html]
4. [https://www.nature.com/articles/s41598-020-58060-0]
Yes, I've been reading those as they come out. Soon, we will have more answers (and maybe more questions!).
Everything in reality does seem to end up working its way back to two or one of something of some kind or other if that makes any sense.
Yes I think it does
Thank you so much!