Your mom gave you ocean bacterial cooties

A Biologist's Guide to Mother's Day

You and I share a mother. It doesn’t matter who you are, whether you’re American, European, African, Asian, or even a hyperintelligent dog reading this newsletter, you and I are relatives.

At least, that’s how modern biologists understand life. The combination of Mendelian genetics and Darwin and Wallace’s Theory of Evolution tell us a story of interwoven ancestry connecting all living things.

The reason biologists believe all living things are descendant from a common ancestor is not because every living thing (except RNA viruses) has DNA, amino acids that fold into proteins, lipids, and other essential building blocks of life. Rather, when we look closer at the DNA we find some common features that are quite difficult to explain if life arose independently and different branches of life have different, independently-originating common ancestors.

Consider your hair. Not all organisms have hair, so I don’t literally mean your hair, although the protein that makes up hair - keratin - is shared across many animals including the feathers of birds, the skin of lizards, and more. An X-ray crystal structure of protein, keratin, is shown below (Bunick & Milstone, 2016).

The protein above is visualized as a fuzzy, knobby, blobby surface, but that surface itself is defined by exceptionally fast-moving, Schroedinger-cat-like electrons that we sometimes describe as particles whirring about, sometimes describe the cloud of where they’re whirring about, and sometimes describe in freakier quantum ways as probabilistic objects whose position and spin are coin-tosses like Schroedinger’s cat until the moment they’re observed.

Your freaky quantum hair, and my freaky quantum hair, is made up of freaky quantum atoms, and those atoms - Carbon, Nitrogen, Hydrogen, Oxygen, Sulfur etc. - are arranged in larger molecules called “amino acids”. Below is a colorful table of essential amino acids:

Chemists use those weird stick-figure diagrams to represent the chemical structures of amin acids, where the vertices of each line correspond to the position of Carbon atoms and all other atoms (Nitrogen, Oxygen, Hydrogen, Sulfur) are indicated by their appropriate letters. The lines themselves correspond to another representation of those fuzzy, freaky, quantum electron clouds in the form of bonds between atoms, electrons shared in an atomic tug-of-war over who gets to have more of the electron cloud than the other.

Okay, so let’s recap: your freaky quantum hair is made of keratin. Keratin is made of amino acids arranged in a very specific sequence to form a regular, fuzzy-looking blob that ends up being essential to the structural integrity of your hair, nails, and skin.

How do organisms arrange amino acids into this specific order necessary to form such a specific, repeatable, necessary protein?

You’ve heard the answer before: The Genetic Code

You’ve heard of secret codes and code-breakers before, so let’s draw a deeper connection here. The enigma codebreaker from World War II, for example, allowed Allied powers to convert scrambled gibberish sent between German military and government officials into intelligible messages.

Below is the Enigma machine that can be used to turn a message into gibberish and then regularly turn the message back from gibberish into legible text

The Enigma worked by a “cipher” or a mapping connecting any one letter to another. Below is an example of a cipher:

For the purpose of encrypting messages, it’s important to continually scramble this mapping, to constantly change the mapping but in a regular way such that only those who need-to-know the message can unscramble the words and read the message you sent them. Encryption more or less works this way, with special protocols to ensure only specific people have the keys required to unscramble messages.

Back to your freaky, quantum hair. Keratin. Amino acids. How does the body make this same sequence of amino acids again and again and again? The Genetic “Code”

Below is The Genetic Code. Notice it is basically a cipher but instead of mapping letters in our alphabet to letters in our alphabet it maps triplets of nucleic acids individual amino acids. This is a one-way code. Your DNA, my DNA, my dog’s DNA, the DNA of every bacterium in your mouth, the DNA of the plants outside your room, every single living thing (except RNA viruses) has DNA packed inside the nucleus like precious books stored inside a secure library. Those books contain the instructions for all of life, analogous to a book with a blueprint for a tractor, and the instructions are converted into real things first by transcribing the DNA to RNA, effectively making a Xerox copy of a small page inside a DNA book so you can take the page outside the library or the RNA outside the nucleus.

The RNA doesn’t contain the exact same nucleic acids as DNA. While DNA contains the familiar letters A, T, G, C, RNA contains nucleic acids corresponding to letters A, U, G, C (instead of T, they have U). An RNA transcript can look like the letters below:

AUG - UCA - UUC - UUA - CUA - UAA

With those triplets of letters, we can go to The Genetic Code above and turn this into our encrypted, amino acid message. AUG corresponds to Met, or Methionine, and so on, yielding the amino acid gibberish:

Met - Ser - Phe - Leu - Leu - Stop

Those amino acids have funky chemical structures we saw above, some of those chemical structures stick together like magnets and others repel like, well, also like magnets, and the sticking & repelling forces cause these amino acids to fold up into those fuzzy blobs like keratin.

It’s not just keratin in your hair, it’s the hemoglobin in your blood, the actin and myosin in your muscles, the antibodies in your immune system, the proteins that mutate to cause cancer, and more. As I’ve highlighted before, we are all bags of bitchy, demanding enzymes, those enzymes are made thanks to the genetic code, and the genetic code is the same in every living thing on Earth!!

If you were snooping around in World War II found another gibberish message that translated into perfect German with the Enigma machine, you could safely conclude that the message originated from someone with that same encrypted system, or that the message has some common cultural evolutionary relationship to the German messages, that these messages have a common ancestor of the first messages encrypted by Germans in WWII.

That’s why we believe all living things have a common ancestor. The is a vast set of ways to map 64 possible three-nucleic-acid sequences into 22 amino acids, yet every single living thing has the exact same mapping, the same Genetic Code, the same biological Enigma.

This has been a very long way to make the following point: you and I are related.

Many people hitched to ideals of human supremacy are uncomfortable with this for various moral and theological reasons. Humans are so much better than chimps at so many things, how dare Darwin and Wallace suggest we are related. Alternatively, if we’re all bags of bitch demanding enzymes related to poop-slinging primates, why be good? For starters, one reason an organism can choose to be good is by selection against organisms that do bad things and then get murdered or executed, and by the direct and indirect reciprocity in our social networks whereby people who do good get favors returned and get admired as good candidates for friends and favor-reciprocation by others who witness the demonstrative act of walking an old lady across the street.

I’m not here to change anyone’s mind, just to present some things I find beautiful in the paradigm of modern biology and evolutionary theory. Namely, if we’re all related, then we can all celebrate today together: Mother’s Day

You and I have a common grandmother preceded by some unknown number of “Great-s”. This is evident not only in the common genetic code, but in something precious that only mothers do: mothers in sexually reproducing species have eggs, and eggs host a special organelle called “mitochondria” that serves as the power plant providing energy for the cell. Your mitochondria come from your mom, my mitochondria come from my mom, and both of our mitochondria are related.

Quick detour for some more freaky biology: I said our DNA is stored safely like library books in the nucleus of the cell, but that’s not the whole truth. We have additional DNA in our mitochondria. However, while the books in the library are bound like traditional books - similar-sized pages stacked together and bound on one side like the codex originating in the first century AD - the “books” we see in the mitochondrial library are figurative hieroglyphs structurally similar to the things we see in Egypt. Precisely, while our mammalian, animal, and “eukaryotic” DNA is arranged in long, linear chunks that bundle together, the mitochondrial DNA in our body is not in a line but in a circle, just like bacteria and archaea, two other domains of life very distant from our own (but relatives nonetheless <3).

How the hell did a bacterial-looking mitochondria get inside our cells in the first place? Nobody really knows, as nobody was there to see it, but the closest contemporary relatives of mitochondria not found inside cells are these funky ocean bacteria. Who knows what happened in some prehistoric marine hot spring, but something freaky happened and it resulted in an ocean bacterium getting inside another cell and then both the surrounding “mother” cell and the intracellular bacteria reproducing together. This freaky night at the marine hot springs created all plant, animal, fungal, and protozoal life as we know it.

These are your great uncles, you freak:

The bacterial genus Iodidimonas is believed to be a close, extant relative of the mitochondria living in our cells. We inherit our mitochondria from our moms.

Okay, recap: we’re bags of bitchy demanding enzymes sharing the same genetic code for making enzymes with all living things. Your mom gave you ocean bacterial cooties. Jokes on me because I have ocean bacterial cooties powering my cells that I got from my mom, too. We’re all powered by ocean bacterial cooties and it’s awesome, it’s another reason to feel gratitude towards your mother and connection with every living thing.

Happy Mothers Day.

I mean it. Every living thing we’re related to shares a mother with us at some point in the distant past. It’s evident not only in our genetic code, but for all of our cousins in the plant, animal, and fungal kingdoms it’s also evident in the funky ocean bacteria living inside every cell of our body, all of which we got from our mothers. Every twitching muscle in my fingers typing this, every muscle moving your eyes, all of the energy burning in your brain to make you conscious, that is all happening thanks to the mitochondria you got from your mom, and both of us got from some ancient mother connecting you and me.

My mom is a biologist. She raised me to appreciate this incredible world of relatives. Like her, I’m also a biologist, so ingrained in the family business that when she was diagnosed with pancreatic cancer, she and I came up with a method to improve the efficacy of her prescribed chemotherapy, and 16 months post-diagnosis she’s shown an extraordinary response to chemo. Her tumor cells shut down, her tumor size shrunk precipitously, and her pancreas now looks normal. I’m feeling exceptionally grateful this Mother’s Day because my mom is healthy, and it may well be thanks to the biology she learned and passed on to me.

My mom was also a world-class mentor for young scientists (lucky me <3). One of her students, Don Ben, was a member of Navajo Nation (there are movements to return their original name - Dine - so let’s use both here). The Dine people view motherhood as sacred, they are a much more maternalistic society than Anglo cultures have been, and I’m thinking of now Dr. Ben today not only to reflect on the value of maternalism, but because Dr. Ben himself grappled with what DNA really means. In an effort to map our Anglo scientific understanding of DNA onto his own culture and traditions, and then map it back into English, he came up with one of the most profoundly wise unencrypted messages I’ve ever read:

“DNA is the story of our ancestors written in every cell of our body” - Dr. Don Ben (Dine)

Yes, we’re bags of bitchy, demanding enzymes made by giant libraries of encrypted genetic codes.

Yes, we inherited freaky ocean bacteria from our moms.

Those are legends in the story of our ancestors written in every cell of our body. This Mother’s Day, I want you to feel just how special that is. Every single mother from the first living organism to your own direct mom etched a mutation here and a mutation there, sometimes a whole intracellular organism in extreme cases, and together those etchings tell a story of every single ancestor connecting you to the beginning of life on Earth. That story of your ancestors isn’t just stacked in a dusty library, it’s translated into existence in every cell of your body. It’s the keratin in your hair and on your skin, it’s the receptors in your eyes detecting light, the hemoglobin in your blood shuttling oxygen from your lungs to your brain, it’s the proteins in mitochondria providing energy to every neuron in your brain.

It’s you, it’s beautiful, and it’s thanks to your mom.

Happy Mothers Day, everyone.