Ancient Human DNA Suggests Twisted Roots at Base of Human Family Tree
Scientists have sequenced DNA from the 400,000-year-old remains of an early human found in the Sima de Los Huesos cave in Spain. It not only shatters the record for the oldest human DNA sequence ever obtained, but is also forcing scientists to question what we thought we knew about human origins.
Traditionally, scientists have compared the measurements and proportions of these skeletons in order to place our ancestors along the human family tree and evolutionary timeline. The skeleton up top, from the Spanish cave, is classified as Homo heidelbergensis, a group of human relatives from Europe who, according to the bones, are thought to be the ancestors of Neanderthals.
But new and powerful DNA sequencing technology has given us the ability to stitch together sequences from older and more degraded DNA samples than we ever thought possible (I wrote about a 700,000-year-old horse sequence earlier this year for WIRED). The sequences in the Los Huesos DNA don’t agree with the old bone story.
The sequence shows that this 400,000-year-old DNA is most related to Denisovans, a group of early humans previously only found in Siberia (AKA “not near Spain”). It was also related to Neanderthals, which fits with the old idea, but suggests that there was a lot of interbreeding and migration going on in these groups, even before modern Homo sapiens had left Africa.
The genomic revolution is changing a lot about science, and the study of human origins is one of the fastest evolving (pun intended). This new info has confused the hell out of scientists, frankly, and there’s a lot of work to be done.
The roots of our family tree tell a twisted and gnarled tale, written in fragmented sentences, but modern technology is beginning to bring those lost words to light. Hopefully they aren’t jibberish.
I’ve got passion in my brain and I ain’t afraid to show it…
Illustration above by Jon Perry, whose animated series about evolution, Stated Clearly, is really worth checking out (also featuring great illustrations of Rosemary Mosco from Bird and Moon!). They have a Kickstarter going to fund more videos, and if you think the world could use more fun and positive ways to teach the beauty of genetics and evolution (and we all know that the world could use more of that), then consider supporting them.
Here’s one of their videos, What Is Evolution?
photosynthetic colour change. photos (click pic) by: 1. justin schmauser; 2. torsten silz; 3. zoomboy1; 4. justin schmauser; 5. anymotion; 6. jim bolden sr.; 7. jaqueline d’ella; 8. zoomboy1: 9. justin schmauser; 10. alister c.
Fall is coming to an end, the sun sinks lower every day, and the chill of early winter has fallen across much of the northern hemisphere.
That means that, in places where leaves actually change color (AKA “not in Austin, where I live”), green has long given way to fiery reds and oranges, and that fire has since fallen to the ground, extinguished by garden rakes or decomposition, or blown out by brisk winds.
Hold on to these macro photos of color-changing leaves as a memory of the passing season. As the days have grown shorter, these plants have stopped producing as much green chlorophyll, and their carotenoids and anthocyanins shine through in bright canary and deep vermillion hues. You can also observe their veins, weaving beneath the leaf’s scaly epidermis, cutting cracks like a drying desert pond.
Here’s a less poetic diagram:
This is the beauty that lies in knowing, the science in the details, the wonder of the changing seasons.
My video on exoplanets this week was inspired heavily by Lee Billings’ book Five Billion Years of Solitude:
This book, which might be my favorite science read of the year, chronicles the past, present, and future of our search for other worlds and other intelligent life through personal accounts of the scientists who have devoted their lives to that study. It’s also a great reference to Gabriel Garcia Marquez, so extra points for that.
In the book, Lee touches on the tumultuous history of Earth’s place in the universe, decades of planetary science in our own solar system and beyond, our persistent search for extraterrestrial intelligence, and what the expiration date might be for life on a changing Earth.
It’s far more than I could ever cover in one YouTube video, so check out Lee’s recent presentation at Google HQ (above) if you’d like to dig deeper.
Reminder! Part 2 of my exoplanets series comes out next Monday, and it will deal with all those mind-bending questions of extraterrestrial life and what our planet’s future holds. Keep your eyes to the skies (and to YouTube)!
Why Moose Fight
In collaboration with the American Museum of Natural History, PBS Digital Studios and ThirteenNY present a new show: Diorama. It does pretty much what it says on the tin, which is to say museum dioramas come to life and are explained by experts!
Yesssss! This is basically what is happening in my brain, and I suspect many others’ brains, when I walk through a museum. I am guessing this series will basically be Night At The Museum, only with far less Ben Stiller and much more science.
Anyway, talking about this episode, moose mating sounds like something I would not want to get in the middle of. And thanks to this video, I will never unhear the female moose moan. But wow is it interesting.
Related to the last, here’s a beautiful (but already out of date) look at the Kepler exoplanet candidates. Kepler detects exoplanet candidates by looking for the dip in light as they pass in front of their parent star.
So many suns out there, some hotter, some colder, but all hugging planets close.
And again, incase you somehow miss me constantly reminding you about it :) … here’s my video all about those other Earths.
(image via NASA)
The New York Times has created an interactive feature tallying all of the exoplanets discovered by NASA’s Kepler Telescope. You should really check out the link, because theirs is animated, and much bigger, and completely awesome, so go check it out.
Although the Kepler telescope is currently dead in the water thanks to some broken gears (although there may be some hope for a resurrection), scientists continue to sift through its data in order to move exoplanets from the “possible” to the “confirmed” category. As of today, we have a total of 1,049 confirmed exoplanets (and counting), which is a drop in a drop in a drop in the bucket for how many are estimated to be out there. Those confirmed 1,049 represent a mere 0.00000001% of the likely 100 billion planets (or more) in just the Milky Way (which doesn’t even count free-floating rogue planets!)
Assuming we continue to fund future missions, the estimates of total planets will certainly change. And as scientists continue to dig through Kepler’s data the number of confirmed planets will definitely continue to rise. Our next steps will be to directly image them (we still don’t know what these exoplanets look like, despite what artists want you to think) in order to analyze the makeup of their atmospheres and whether they have the right chemistry for life (at least as we know it). That will take new tools, and decades of work.
Thanks to planet-hunting missions like Kepler, we are on the cusp of understanding our place in the universe more clearly than ever before in the history of our species. We may be the only living needle in the haystack of planets, or we may not. That distinction isn’t what makes us special. No … what makes us special is that we can know.
Double Bonus: Find out more about how astrobiologists calculate the odds of extraterrestrial civilizations in this episode of It’s Okay To Be Smart: The Odds of Finding Life and Love.
(this is an updated version of a post from earlier this year)