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Mitochondrial Eve — Description

Oh my gods. I finally get to do it. This is my moment, at last, to shine as a real teacher! Class, this will be on the test: the mitochondria is the powerhouse of the cell. It's also an alien symbiote. No not really, I just finished my playthrough of Spider-Man 2, but now you're listening further than you did in real school. Only half of that, it turns out, is untrue though.
For the select few out there for whom the mitochondria is not the only thing you retained from the American education system, let's get the basics out of the way. This is gonna get real sciency real fast and even I, an actual lab-trained scientist, views chemistry as unparsable witchcraft. The cells in your body are effectively lego goop inside of a soap bubble, and because you are a eukaryotic lifeform, your soap bubbles come pre-packaged with even tinier soap bubbles called organelles, each fulfilling a different biological requirement for your little Lincoln log robots. One of those precious functions you need in order to remain sentient meat is cellular respiration, the process by which you intake oxygen and glucose (air and food) in exchange for ATP, adenosine triphosphate. ATP is an energy-storing molecule which works kinda like a handheld flare, you snap the end of it off and it shits out a bunch of free energy to power the water wheel that is a living thing, and the bulk of these body batteries are created in an organelle specifically engineered for that exact purpose: the mitochondria.
Mitochondria were first taken note of in 1857 by a Swiss neurologist named Albert von Kölliker, though he only described them in passing as curious membraned granules which seem to be present in pretty much all the insect cells he was studying. They weren't further investigated until 1890, when German histologist Richard Altmann penned these critters as “bioblasts” (the term “mitochondria” meaning “thread granule” wasn't coined until eight years later by Carl Benda). Altmann surmised that these must be what he called “elementary organisms” living inside of cells symbiotically, and as it turns out, he wasn't wrong. Mitochondria already bear a striking resemblance to independent species of bacteria (specifically genus Rickettsia, which confusingly has nothing to do with rickets), and they even reproduce independently from the rest of the cell. I mean kinda, like your cells still give it a little chemical zap to initiate it but the mitochondria itself still has to go through its own mitosis.
“Looks like” is not good enough in science though. Plenty of pieces of toast look like the face of Jesus, afterall, so while this hypothesis of endosymbiosis had its devoted community of vocal supporters (Carl Sagan's kooky ex-wife Lynn Margulis the loudest among them), we were missing the steps required to prove these oddities weren't just one of several wacky processes evolution has shat out by the seat of its pants. The door for that proof was unzipped in 1953, with the discovery of DNA's helical structure by Watson, Crick, and Franklin. Now that we could actually read the instruction manual for how to build an organism, we could dissect it for discrepancies and trace its mutations. Mitochondrial DNA specifically was isolated by Margit and Sylvan Nass in 1963, and the complete mitochondrial genome was sequenced in 1981. Come to find out, the mitochondria has its own completely separate genome, distinct from your nucleic DNA and recognizably bacterial. Endosymbiosis is now justified as a pretty irrefutable theory, though we're still working on the exact mechanism of how. The math of common descent of all organisms with mitochondria alive today gives us an approximate window into a world 2 billion years ago, when some breed of archaea gobbled up a bacteria and just sorta… kept it. Today's topic though, sadly, is not the origin of eukaryotes, so I have to stop myself before I trigger paleontologist mode and spiral us down a completely unnecessary tangent.
Here's where it becomes relevant to your filthy monkey species: your mtDNA is an inheritance you receive exclusively from your mother… usually. See at your core, you begin your fetid existence as a Dragon Ball fusion of two genetically distinct cells: the egg of your mother and the sperm of your father. Each of these cells come pre-packaged with their own mitochondria, but in sperm they're all sorta coiled up inside the neck of the tail. In mathematically perfect biochemistry, this does not factor into the equation. During fertilization, it's only the head of the sperm that jacks into the egg cell and deposits the genetic payload. We live in an extremely glitchy universe though, where things quite literally slip through the cracks. Egg cells actually have an entire mechanism built in to account for a bit of tail getting overzealous with its penetration, destroying male mitochondria on contact to prevent admixture. It's not unheard of for a patient to present with disorders that can only be attributable to their father's mitochondria, however. The human machine is a disgusting flesh bag which does not operate to the gold standard we'd like it to. At worst though this is a 1 in 5000 sort of error, and so far as I can tell, current literature asserts that it does not statistically affect the conclusions we're about to draw about the history of our species we're about to go into. Now that we're all good little microbiologists with dotted i-s and crossed t-s, it's time to dig into the real lynchpin of today's topic: the tragic inevitability of incest.
I am a descendant of Charlemagne. It's one of those things you're bound to stumble across if you're a lucky enough bitch to trace your family tree beyond the 1500s. It's also one of the least special things you can possibly imagine. I am not royalty and I think being famous is a drull and short-sighted shadow of existence. If you see people squawking around boasting claims of descent from medieval royalty, then they don't understand how genealogy works. Everyone alive today with reasonably recent European ancestry is a descendant of Charlemagne, and I can mathematically prove it. You have two biological parents I… I presume. If you don't then please tell me your story, that sounds like a hell of a tale. Assuming you are among the 99% of humans who work like everyone else though, you have two. Your parents, in turn, have two parents of their own, resulting in four grandparents. In turn, you have eight great-grandparents, sixteen great-great grandparents, and so on. These exponential numbers get really big really fast. If you were to assume that you have an unbroken tree of individual unrelated ancestors throughout history, then after just 33 generations there would be more unique people living at the dawn of the Renaissance than there are currently alive as you're reading this in the Denny's parking lot, and then double that amount if we go back just a single generation more. That's not compatible with reality. There were only about 300 million people on the entire planet when Joan of Arc was being spit roasted, and the only way that number got any higher was because our only available mates in a time before planes, trains and automobiles were our cousins living in the same peasant village. You, me, King George III, and that crackhead on the East Side are all cousins somewhere down the line, the imbred bastard results of surprisingly few generations of cousin-fuckers.
Because of this uncomfortable reality, for any given population size, there is a mathematically determinable date at which every single human alive back then must either be a direct ancestor of every individual in the modern population, or else their lineage has died off completely. This is formally referred to as the “Identical Ancestors Point” or IAP. For individual countries or whatever vague categories of ethnicity we try to lump each other into for some reason, the IAP usually shakes out somewhere between 30 to 50 generations. So a thousand or so years back, every single person of European ancestry must have identical ancestors to anyone else of European ancestry alive today, including royal families. If one person is a descendant of Charlemagne or Confucius or whatever have you, then everyone else must be as well. Being of royal or divine blood is not unique to a single human being on this planet, take that lesson however you like.
Let's put this all together now: because your mitochondria is a maternal inheritance with its own separate genome, we can calculate a universal female common ancestor which every single human alive on planet Earth today descends from, whether they're selling tourist brochures in Egypt or erecting Moai in the middle of the Pacific. In 1987, geneticists Rebecca Cann, Mark Stoneking, and Allan Wilson of the University of California submitted a paper to the journal Nature detailing their experimental conclusions on exactly that. Taking mtDNA samples from 147 human placentas (I… I don't know why specifically placentas, don't ask me) from different populations around the globe, it was determined that we all descend from a singular woman who lived around the Great Lakes region of Africa, roughly between 150,000 and 200,000 years ago. Professor Cann got a flood of hate mail for this discovery, because apparently we were still pushing back against a blatantly obvious African origin for our species in 1987. In a 2002 documentary titled The Real Eve, Cann recalls getting a Christmas card from her own uncle with the words “How dare you? You know grandma wasn't black!” angrily scrawled on it. Jesus Christ people, this is why we don't invite you racist losers to parties.
Now there's a few common misconceptions I should do my duty to clear up: this woman, whom Cann's team poetically dubbed the “Mitochondrial Eve”, was not the first female of species Homo sapiens. The oldest fossils of anatomically modern humans we have on record are the 300,000 year old remains from Jebel Irhoud in Morocco. That means Mitochondrial Eve lived anywhere from an entire third to a half of the way through the whole existence of our species. She was also not the only woman on the planet, which sounds like a hellish sort of isolation. There were plenty of other hot ladies hunter-gathering across the motherland at the same time, they just didn't leave behind any surviving descendants. The Mitochondrial Eve is simply the most recent woman from which everyone alive today commonly descends, our shared grandmama who lived a perfectly average life surviving with her tribe in a valley of four-tusked elephants and unrecognizable constellations. She also notably lived in a completely different time and place to her masculine counterpart, the Y-Chromosomal Adam, but I'll touch on that in his own blurb.
Unfortunately there's not really anything we can realistically glean about the culture of this woman. We'll never know her name, we'll never know if she was even a good mom or not, we'll never even know if we have her bones stashed in a museum archive somewhere. She would've lived somewhere between Lake Tanganyika and Lake Malawi, an area rich with ancient hominid fossils. The most culturally notable archaeological site in this region is Kalambo Falls, which boasts the oldest surviving man-made wooden structure on Earth, made around 476,000 years ago, probably by Homo heidelbergensis or Homo ergaster depending on which paleoanthropologist you wanna get into a fist fight with today. So hey, there's a nonzero chance the Mitochondrial Eve actually lived in a house, something I'll never be able to do! Good for her! She'd be setting up shop right next to an active volcano though. Mount Rungwe is an unrealistically beautiful scene which interestingly enough sits smack in the middle of the African Rift Valley. This is a massive crack in the Earth that runs from the Afar Triangle in Ethiopia all the way to the Okavango Rift Zone in Botswana, formed by the violent divorce that is currently in the works between the African, Somali, and Arabian tectonic plates.
This unique geography actually helps shed light onto some pretty fun implications for how Mitochondrial Eve's descendants migrated across the world. Think about it: you're born in a giant canyon, there's really only two options for leaving your geographical locality. Follow it north, or follow it south. Lo and behold, we see this play out in the phylogeny of descent we're able to reconstruct from its root, known in genetics as “haplogroups”. Referencing 2013 a paper by Rito et al, it seems this first population split diverged from the Mitochondrial Eve's lineage around 130,000 years ago. One branch, haplogroup L0, followed the Rift Valley southwards, and is primarily clustered today among the peoples of south eastern Africa, most heavily in Khoisan-speaking populations. Circling back to our old pal racism again, I would like to point out that no, this does not mean that the Khoisan are the “first people” or the “oldest people” as so many headlines would have you believe. Just because they live a mostly hunter-gatherer lifestyle does not make them “more primitive” than anyone else or some kind of stone age “living fossil”. There is nothing in modern Khoisan lifestyles which can in any way give us insight into the culture of the Mitochondrial Eve. Their beautiful languages and resonant stories have undergone just as much change and adaptation as everyone else on this rock, and they deserve to be approached and studied with the dignity owed to one of thousands of unique descendants of this common ancestor of all humankind.
Haplogroup L1 meanwhile followed the valley north and vered westward into the Sahel, quite literally finding greener pastures thanks to a humid period that was effecting North Africa around this time. Ever notice how the Sahara Desert cuts off abruptly between the Equator and the Tropic of Cancer? And how south of that line is the climatic opposite, the lush impassable rainforest of the Congo? Every few tens of thousands of years or so, that situation reverses. The rains migrate northwards into the Sahara, turning it vibrant and green, abandoning the southern lands to desertification. This is because Earth's orbit around the sun is wobbly and unstable, its momentum sometimes “stretching” one side of the orbit and flipping the Earth's latitudinal climate accordingly. Formally we call these Milankovitch Cycles, and the specific effect it has on Africa is referred to as the “Sahara Pump”, because it inherently forced our ancestors to not remain in one place for too long, driving migration to follow the food and shelter.
L1 is primarily clustered around the foragers of Central Africa, especially those peoples living in the vicinity of Mount Cameroon. Its closest cousin meanwhile, branch L2, is pan-African and seems to have emerged about 100,000 years ago (as estimated by Silva, M. et al in 2015). Haplogroup L3 seems to represent the peoples who stuck more loyally to following the Rift Valley north into Ethiopia, eventually coming across the superhighway that is the Nile River. Whether it was via the Sinai Peninsula or skipping across the Red Sea from the Afar into Arabia, L3 is the haplogroup from which all peoples outside of Africa descend, representing a migration of folks who left their ancestral continent around 70,000 years ago to see what else this world had in store for us. It should be noted that these were not the first humans to leave Africa. The oldest Homo sapiens remains outside of Africa which everyone can universally agree on were found in Misliya Cave in Israel, dated to about 180,000 years old. The L3 migration just happens to be the only one with living genetic descendants. These are the brave folks that opened the rest of our planet to us, the family that found the ruins of Toba, the tribe who heard the last words of the last Neanderthal, the people who left footprints in the white sands of New Mexico. We've come a long way, us descendants of Eve, but no matter how far we traveled, we have always been home.
Design notes, so this was a curious conundrum, because in order to design an outfit for this woman I had to wrestle with the incredibly fragile subject of prehistoric clothing. Cloth fibers do not preserve well in the archaeological record, they're delicate and quick to decompose. The oldest article of clothing we have in the archaeological record is a women's dress excavated from the Tarkhan necropolis just south of Cairo, dated to about 5000 years old, nowhere even close to the minimum 150,000 years ago the Mitochondrial Eve lived. The oldest preserved rags of recognizably woven textiles meanwhile are the 8500 year old bast fibers for wrapping the dead at Çatalhöyük in Turkey, while the Judean Desert preserved a 10,500 year old woven basket in a cave near the Wadi Murabba'at, so we clearly had weaving technology by the Neolithic at least. 30,000 year old dyed flax fibers were discovered in Georgia's Dzudzuana Cave, though fibers are all they are. Harvard archeologist Ofer Bar-Yosef proposed that rather than being tightly pressed into sheets of linen, these fibers were probably instead used to make macramé constructions not dissimilar to the ones decorating your grandma's house. Farther afield and roughly contemporaneous, the Sungir site in Russia preserves graves with skeletons absolutely bejeweled in intricate patterns of ivory beads carved from mammoth tusk, insinuating that our species had a kickass and highly advanced fashion sense even during the ice age.
Unfortunately, we kinda have to surrender to context clues to push the prehistory of clothing any farther back than that. Denisova Cave contains the oldest known sewing needles at 50,000 years old, fascinating because that implies even other species of human had sewing technology, while somebody about 70,000 years ago left our oldest documented bone awls in Blombos Cave, in South Africa. Then there's our parasites, that vast microscopic ecosystem that considers you its planet, evolving in tandem with our history. In 2010, Toups et al. estimated that clothing lice genetically diverged from human head lice at some point between 83,000 and 170,000 years ago, the authors themselves preferring the latter date because it syncs up nicely with Marine Isotope Stage 6, an ice age that would've put selective pressure on humans to invent warmer coverings, i.e. clothes. What those clothes would've looked like though, and how they were constructed, is a complete mystery. It's possible the earliest clothes were just animal hides draped over the body and held together with fibrous cord of sorts. We have hide scrapers as old as 780,000 years from the Gran Dolina cave in Spain, so we know ancient humans had access to animal skins at least, but of course that doesn't necessarily mean they were wearing them yet, plenty of other uses for a good roll of leather out in the wild, after all.
For my part, I decided that cord-and-hide aesthetic was both the most justifiable and just a fun option to explore. I also threw some beadwork in there because I'm extra and who doesn't love that Sungir chic? I feel like people tend to go two directions when it comes to designing prehistoric peoples. Usually they take the Flintstones route and just sorta haphazardly Frankenstein some stitched leather and furs over the character, usually with some kind of Native American-adjacent bone jewelry because that old “Noble Savage” chestnut is still lingering in our society. It's either that, or it's an early 2000s documentary talking about prehistoric Homo sapiens in Africa… and then using footage of modern day hunter-gatherer tribes in Africa as the stand in. I don't like either of these approaches, they're uninspired. And racist. I want to see more cavemen draped in macramé. They were people, give them some dignity. Imagine hunting a mammoth in a cape of grandma's drapes, that's a fuckin powerful image right there.