There Are ‘Ghost’ Humans in Our Genome - We Just Found Out Who They Were

Añadido: 2026-05-21

[00:00:00]Hello and welcome to 7 Days of Science.

[00:00:02]This week, we're looking at an incredibly exciting new study that appears to have unraveled the identity of the mysterious, superarchic ghost humans lurking within our genomes.

[00:00:24]The human genome contains a complex ancient story of our evolution. From our earliest single-sellled ancestors, this remarkable biological instruction manual has been added to, edited, and swapped between species for billions of years, eventually becoming the guide for making a modern-day human. But our genomes contain a multitude of mysteries. From the dark genome made up of remnants of prehistoric viruses and so-called rogue DNA to the parts of our genetic code that were passed to us from now extinct human species, there's still so much to learn about our very base nature and about what exactly makes us human. One of the most intriguing genetic mysteries concerns the identity of the so-called superarchic humans who contributed to the genomes of certain modern populations in Asia and Oceanana. It's been well known for many years now that ancient members of our species, Homo sapiens, struggled to keep it in their pants when encountering other human species. Interbreeding with Neanderals, occurred on many occasions, and parts of their genome survive today thanks to these prehistoric trrists. In various populations in Asia and Oceanana, as well as among indigenous Americans, there's evidence of ancient interbreeding with another now extinct human species, the Denisven. For several years, Denise were known only from fragmentaryary fossil finds of bones with distinct genetic signals, as well as the traces of these people found as genetic remnants in modern-day human populations. However, over the past few years, several papers have reported fossils, skulls, and jawbones that have been proposed to belong to members of this mysterious prehistoric human species, such as the spectacular harbin cranium from northeastern China.

[00:02:12]Denisphans appear to have been most closely related to the Neanderals, likely diverging from them sometime before 380,000 years ago. So there's plenty of evidence that Neanderls, Denisven, and Homo sapiens interb bred with one another at multiple points in the past wherever they came into contact. But what about those superarchic ghost humans? Who were they?

[00:02:36]Well, there are regions of the Denisven genome that appear to have got there as a result of what has been termed superarchic introgressions. That is, the Denisvens got it on with some kind of even more ancient lineage of human one that diverged from us Neanderals and Denisvens at a much earlier point in time. Later on, when the ancestors of certain modern homo sapiens populations interbred with Denise after arriving in the regions where they lived, some of these superarchic regions were then passed onto their descendants and ended up getting preserved to this day. This week, new research has been published analyzing enamel proteins that were extracted from fossilized teeth thought to belong to the superarchic human species Homoctus. This species was a remarkable hominin, probably being the first member of the genus Homo to leave Africa where they originated some 2 million years ago and to spread to Europe and to Asia. In Indonesia, there's evidence of Homo erectus potentially surviving until as recently as a 100,000 years ago. So, this was a very long-lived successful species of human. Before this study, the only molecular data that had been recovered from Homo erectus remains were extracted from a 1.8 8 milliony old tooth unearthed in Georgia. However, there was insufficient information to establish genetic differences that distinguish homoerectus from other human lineages.

[00:04:00]Now, this team of researchers has been able to analyze amino acid varants from the enamel proteins of six homoerectus teeth dating to around 400,000 years ago during the middle pleaene epoch, providing a rare genetic glimpse of their molecular biology. All of these teeth were unearthed in China and five of the teeth were from males while one came from a female. The results of this analysis have revealed that there are two rather interesting amino acid variants that are shared by all the specimens. One of these variants is entirely unique to these sampled homoerectus specimens and is not seen in any other human lineage sampled so far.

[00:04:40]The second variant though has previously been found in Denisvens. According to this study, this variant may therefore have been introduced to the Denisvens via an interbreeding event with superarchic humans related to these homoerectus individuals from the middle pleaene. Furthermore, they therefore hypothesize that the superarchic regions in Denisven genomes are likely to have originated from homo erectus itself, meaning that the superarchic remnants that live on in some modern humans could have also come from them as well.

[00:05:14]Because of that first amino acid variant they found, the one that's unique to these sampled fossils from China and not found in any other humans, it would mean that the particular middle plyene homoerectus population sampled in this study would probably not have been directly involved in interbreeding with Denise. Instead, it would have been other homoerectus populations closely related to this sampled one that likely bred with them. This study is therefore a very intriguing glimpse at the potential identity of those mysterious superarchic remnants in the human genome. And it's quite astounding to think that they could have come secondhand from Homo erectus. Of course, it's important to be slightly cautious with studies like these and there are still numerous mysteries left. For one thing, it's possible that Homoerectus as a grade of super archaic human could end up needing to be classified as multiple different species of homminin since they were so apparently widespread and long-lasting. So, this might not be the final identity of those ghost humans.

[00:06:16]Plus, of course, there's evidence of other instances of interbreeding with possible super archaics in different human populations. And it's important to note some researchers have questioned the certainty with which the tooth fossils used in this study were identified as homoerectus rather than as other examples of denisvents.

[00:06:35]Nevertheless, it's a fascinating point of discussion and we always look forward to finding out more about the various prehistoric humans we once shared our world with. Now, where's the other science news this week is what you're probably asking. Well, we're trying something a little different. We've noticed that what people seem to enjoy and engage with the most are our 7 days of science specials where we undertake deeper dives into particularly fascinating science stories. So, we thought we'd experiment with making our regular weekly episodes focus on one major story of the week and explore the topic in a little more detail than we usually do. But don't worry, we're not completely ignoring everything else that's happened in these last 7 days of science. The other new stories that would usually be included in one episode will be released daily as shorts. So, it's the same content with a bit more detail for the title story, but scheduled differently. To be totally honest with you, we've always wished 7 Days of Science would do a little bit better than it does. YouTube is our actual job. It's not just a hobby anymore. Shorts have increasingly been the way to go for content creators to reach new audiences, and we've never really tapped into it well enough. This doesn't mean that we'd ever get rid of the main 7 Days of Science video, nor are we ever going to switch to making just shorts on Benji Thomas or Douggee James. But for 7 Days of Science, we're hoping this can be a more effective way to reach more people and spread the love of science further. Plus, since people are clicking for the title story anyway, why not give a bit more time to the main event? But if everyone really hates it, then don't worry. We can go back to the way episodes were originally structured.

[00:08:08]We're always up for experimenting with new formats. So, let us know what you think or if there's another style that might work better. To that end, be sure to look out for the other science news we'll be talking about over the next 7 days of science. We've got a great mix of stories from a giant new dinosaur species found in Thailand to evidence of Neanderal Dendustry and somehow string theory returned. You won't want to miss what's coming up this week. You can follow 7 Days of Signs on Instagram and also be sure to support us on Patreon if you enjoy what we do here. As always, a big thank you to our patrons including Andrew Cowam, Brain Weevil, Kang Yin, Chippy Chippy, Chappa Chappa, Diana Hernandez, Drove Shreala, Ethan Wang, Gabriella, Gary Arrington, Guillotist, Iraq, John French, John Perie, Joseph Ree, Josh Lambert, Joshua, Cory Peterson, Lenan Lampkins, Lena Rose, Lewis Fischer, Lou, Mark Nevin, Mendikant Frier, Mike Pace, Ralph Bullzac, Robert Priika Jr., Robert Thomas, Salvin, Sammy Petrikus, Steve Bradshaw, Thomas F.

[00:09:13]Conroy III, Timothy N. Tedro, Tracy Merfield, and Troy Schmidt. Thanks for watching and we'll see you next week.

[00:09:22]We'll see you tomorrow actually. There you go. Fun.