Note (12/2015): Hi there! I'm taking some time off here to focus on other projects for a bit. As of October 2016, those other projects include a science book series for kids titled Things That Make You Go Yuck! -- available at Barnes and Noble, Amazon and (hopefully) a bookstore near you!

Co-author Jenn Dlugos and I are also doing some extremely ridiculous things over at Drinkstorm Studios, including our award-winning webseries, Magicland.

There are also a full 100 posts right here in the archives, and feel free to drop me a line at with comments, suggestions or wacky cold fusion ideas. Cheers!

· Categories: Biology, Genetics
What I’ve Learned:

Mitochondrial Eve: Making DNA from an ooooooold family recipe.
“Mitochondrial Eve: Making DNA from an ooooooold family recipe.”

Imagine your DNA is a brown bag lunch. Your parents packed it with everything you need. A banana, if you like those. PB&J, maybe — unless your particular DNA makes you allergic to peanuts, in which case, I don’t know. Pizza? Fish heads? Who am I, Andrew freaking Zimmern?

The point is, your DNA comes from both your parents, in more or less equal amounts, and it’s stored in each of your body’s cells in something called a nucleus. That’s the bag in this analogy. Or the kick-ass Tardis lunch box, if you prefer.

Anyway, as she often does, your mother left you a little something extra.

But instead of a “love you” note or an extra Twinkie, our moms gave us something else: a bonus stretch of DNA, passed down only from mothers to children. This DNA is housed in a separate subcellular sack called a mitochondrion. Mitochondria do some pretty amazing things, but that’s a whole other bucket of lunches, so let’s stick to the DNA.

Because mitochondrial DNA is passed straight from mother to child, it can be traced back to earlier generations. Variations in DNA occur at a steady rate, and these get passed down, too. By comparing mitochondrial sequences between individuals, scientists can estimate how closely related they are — the more variations they share, the closer they are. If their DNA variations don’t overlap, it indicates they’re swinging on different branches of the old family tree. When a branch diverges enough to represent a unique DNA signature, it’s called a “haplotype” — a pattern of DNA variation shared by all the members of that branch.

Back in the 1980s, scientists tested mitochondrial DNA from more than one hundred people from different populations and found something unexpected: the variations between subjects suggested that they were all related, anthropologically speaking, by a common female ancestor who’d passed her mitochondrial DNA down the line. The research suggested that everyone in the entire human race shares the same great-great-great-lots-and-lots-more-greats grandmother. And we’re all rocking gently-used, slightly-mutated versions of her mitochondrial DNA.

This ancestral individual is technically called our matrilinear most recent common ancestor, or MRCA, but is more informally known as “mitochondrial Eve”; her maternal genetic makeup is represented in all of our DNA. She’s also been described as the “lucky mother”, since she wasn’t the only woman walking around and having babies at the time. Rather, her lineage — including mothers having daughters, since mitochondrial DNA is only passed by mothers, remember — is unbroken through history, while other childbearing ladies of the time had only sons, or no children, or their daughters didn’t produce more daughters down the line.

The idea of mitochondrial Eve shook science to its lunchtime Twinkies, because it implies a couple of things about human history. First, there was a time (or several) when our population must have been very small, maybe on the verge of extinction. For only one woman’s genetic imprint to have survived, rather than many, suggests there weren’t a whole bunch of humans running around the planet already, with haplotypes of their own. Our species went through some rough times, and only one branch of the tree survived.

The DNA also tells us roughly when this mitochondrial Eve existed. Based on the variability between contemporary humans’ DNA and the rate at which DNA glitches occur, mitochondrial Eve probably lived around 100,000 to 150,000 years ago. And since other evidence suggests that early humans didn’t migrate from Africa until about 95,000 years ago, our ur-granny most likely lived there. And cooked up some nice bits of DNA we’re still using today.

(For the record, we can also trace an “ultimate grandpa” via male lineages and the men-only Y chromosome. The “Y-chromosome Adam” may have lived around the same time as, or tens of thousands of years before, mitochondrial Eve. Their DNA’s early paths are completely independent.)

So next time you’re eating a sack lunch, root around in the bottom a little. Not only might you find a nice note — or a delicious snack cake — but you might discover some 100,000-year-old genetic material, courtesy of mitochondrial Eve. DNA appetit.

Image sources: Alvin’s Enviro Blog (mitochondrial Eve map), Sierra Club (fishy Zimmern), ThinkGeek (Tardis lunchbox), PlanetKris (mitochondrial mom joke)

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· Categories: Chemistry, Physics
What I’ve Learned:

Transactinides: They're not heavy. They're your metals.
“Transactinides: They’re not heavy. They’re your metals.”

The transactinides are a group of fifteen elements — fundamental building blocks of matter, like carbon or hydrogen or double-sided duct tape. But transactinides are pretty special elements, in a number of ways.

First, the transactinide elements are all radioactive, which means they spontaneously split apart into other elements, releasing energy in the process. What’s more, these elements are highly volatile — even the most stable break down within about twenty-eight hours. Much like that drama major you dated back in college.

Transactinides are also the heaviest elements known to exist — and none have ever been detected in nature. We’ve only found them in the laboratory, by cramming atoms of smaller elements together until they stick for a few seconds, like some kind of chemically-unstable PB&J.

(I don’t know what a PB&J decays into, exactly. Strawberry Pop-Tarts? A jelly doughnut? Uncrustables?

This is why you don’t see many snack-related analogies in chemistry textbooks. Clearly, sandwich science is still in its infancy.)

These elements are so bleeding-edge, they don’t even get real names until they’ve been produced in a lab and the results tested and repeated. At that point, a newly “confirmed” transactinide is usually named in honor of someone important to science. Like Rutherfordium was named after physicist Ernest Rutherford, or Seaborgium for a race of Doctor Who villains, I think, or Livermorium, which was named after something a bird said in an Edgar Allen Poe poem. Science is all over the map sometimes.

But before those fancy names, the more theoretical transactinides get systematic titles to identify them. These provisional names are built from Greek and Latin roots for numbers, smooshed together like the ephemeral atomic phenomena they describe. So the element with atomic number 113, for instance, is currently called ununtrium, while the heaviest transactinide, with atomic number 118, is ununoctium.

(Nobody in science really uses these names, for two reasons. First, it’s simpler to just say “element 118”. And second, nobody wants to spend their career trying to produce something that sounds like a disease you get from licking raw chicken meat.)

While most of the periodic table is well established at this point, physical chemists still work on transactinide elements — usually trying to produce the ones not yet confirmed. Just this week, element 117 — or ununseptium, if you prefer your science Gregorian chant-style — was confirmed by a lab in Germany. It was first synthesized by a joint American-Russian team in 2010, who fired a beam of heavy calcium isotopes into a bunch of berkelium atoms to get the job done.

That was a challenge in itself. Berkelium currently only exists on this planet as the result of synthesis experiments and “nuclear incidents” — like an H-bomb test, or Chernobyl disaster.

Also, berkelium’s half life is less than a year, so if the scientists couldn’t agree quickly about how to do the experiment, the berkelium they made for it would have already turned into something else.

So basically, this marks the only time in recorded history when Americans and Russians have gotten their shit together in short order to produce something good. From sammiches to glasnost, is there anything transactinides can’t do?

Image sources: Chemicool (ununseptium), Wikipedia and Philica and Smuckers and and SodaHead (PB&J decay), What Culture (Cybermen/”Seaborgmen”), GlobalResearch (Putin/Obama)

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