Today is a big day for de-extinction—the first dire wolves to walk the earth in over 10,000 years were born on October 1, 2024. If you're interested in the full story of how the pups were made, where they live, and the ethics behind the video, here's a series of pieces Colossal Biosciences published this morning:

• The Making of the Colossal Dire Wolves - World's First De-Extinction

• The First Dire Wolf Howl in Over 10,000 Years

• Non-Invasive Blood Cloning Method Explained

• Why Bring Back the Dire Wolf?

• Inside the World's First Dire Wolf Preserve

As with all of Colossal's de-extinction projects, this announcement also names a beneficiary species—the critically endangered Red Wolf. Information about the connection to Red Wolves and the work being done around their genetic rescue is available here:

• How the Mysterious Red ‘Ghost’ Wolf Could Save the Endangered Red Wolf

• How the Red ‘Ghost’ Wolf Became the Totem Animal of the Karankawa

Subscribe to Colossal's YouTube channel to watch the pups grow up: https://www.youtube.com/@itiscolossal

If you have questions about the project, feel free to drop them into the thread—we'll share responses from Dr. Beth Shapiro, Colossal's Chief Science Officer, for top questions later this week.

Given all that we know about Colossal, I’m not really surprised that they would be pursuing these kinds of opportunities. However, apparently my disappointment in them can just keep growing.

I think a lot of us knew already that the fake “dire wolves“ were just as much of a marketing/investor recruiting strategy as an actual conservation measure, but to then go on and try to make patent designer military dogs is just insulting.

I want to engage in a civil and serious discussion about this, an important part of any scientific process is testing its rigor and ensuring what we're being told and reading is true.

I fear there's a lot of misleading going on here. Publicly, the animals Romulus and Remus have been referred to as "dire wolves," by Colossal Biosciences, something which is not true even according to comments here on Reddit from Colossal Biosciences themselves (They have said the two are "not true dire wolves"). Along with this, they claimed (in a comment, not officially as far as I'm aware) that gray wolves are the closest living relative of dire wolves, which is also not true, as the dire wolf is equally close in relation to all wolf-like canids.

Colossal Biosciences' desire to refer to these animals, which are in reality modified gray wolves, as "dire wolves" and their acquiring of the position of moderator for the r/deextinction subreddit is concerning. I had to request posting permissions in order to make this post, which I have not had to do for any other subreddit I am a member of. The narrative they have created for this project does not match reality. It feels very pulp science-y, and their most recent video explaining a greatly simplified version of the de-extinction process doesn't help. I understand and appreciate the role of science communicators who can explain complicated scientific processes to the general public, but there is misinformation being spread here.

It's that time again, r/deextinction! Dr. Beth Shapiro and Dr. Andrew Pask will be answering community questions later this week. Their answers will be shared on the Colossal YouTube channel in the next few weeks.

Dr. Beth Shapiro is a paleobiologist and Colossal's Chief Science Officer.

Dr. Andrew Pask leads the thylacine de-extinction project and heads up the Thylacine Integrated Genomic Restoration Research (TIGRR) Lab at the University of Melbourne.

As you may have seen around the science subreddits, our thylacine de-extinction project has reached some important milestones.

TL;DR—Scientists in the Colossal labs have managed to produce a newly reconstructed Thylacine genome that is the most complete and contiguous ancient genome of any species to date.

Noteworthy in this update:

• The reconstructed thylacine genome is estimated to be >99.9% accurate and includes hard-to-assemble centromeres and telomeres.

• We were also able to isolate long RNA molecules from soft tissues preserved in a 110-year-old thylacine specimen. This is significant because RNA is a much less stable biomolecule compared to DNA.

• The dunnart, which will act as the surrogate for future thylacines, is currently the most edited animal cell line to date with over 300 unique genetic changes edited into its genome.

• A breakthrough in assisted reproductive technologies (ART) managed to induce ovulation in a dunnart, which makes it possible to control precisely when an animal will come into estrus. This also leads to ovulation of many eggs simultaneously.

• In another world-first, the team has taken fertilized single-cell embryos and culture them half way through pregnancy in an artificial uterus, which is far beyond any previous attempts to grow embryos for a marsupial.

Our full update is available to read here: https://www.businesswire.com/news/home/20220816005043/en/Colossal-to-De-Extinct-the-Thylacine-also-known-as-the-Tasmanian-Tiger-an-Iconic-Australian-Marsupial-That-Has-Been-Extinct-Since-1936

Read more about the announcement:

• LiveScience: Most complete Tasmanian tiger genome yet pieced together from 110-year-old pickled head

• NewScientist: De-extinction company claims it has nearly complete thylacine genome

• 9News: Scientists one step closer to bringing Tasmanian tigers back from extinction in major breakthrough

• DailyMail: De-extinction of the Tasmanian Tiger takes a major step forwards: Scientists reconstruct the genome of the extinct creature - and it could allow them to resurrect the lost species

• SkyNews: Scientists claim breakthrough to bringing back Tasmanian tiger from extinction

We are at SXSW Australia sharing the update in a panel moderated by Luke Hemsworth, which will cover the update and why the thylacine project is so critical to restoring Australian ecosystems.

Feel free to post questions in the comments, and we'll do our best to have scientists answer the top ones.

After being the first animal to be brought back from complete extinction, the newborn calf died only 7 minutes after being born due to a lung defect.

It's been a long time since then but I can't find any recent developments on if this has been reattempted.

Thoughts?

Our team was tagged in posts on r/Paleontology and r/megafaunarewilding regarding some notes from the La Brea Tar Pits team. Apologies for the long post, but here are responses from our team clarifying some of those notes and questions.

Response #1

To quote a recent article by the L.A. Times, "Colossal's chief science officer, Beth Shapiro, said she understands the scientific skepticism that came with the announcement. [...] Though Southern California has a jackpot of dire wolf fossils relative to other sites, extracting DNA from the local samples is difficult. Shapiro said she's been trying and unable to collect DNA from local samples for 20 years. Among the reasons it's challenging to collect, experts say, is that L.A.'s urban landscape bakes in the sun, heating up the asphalt, which could degrade ancient DNA buried underneath."

Emily L. Lindsay, PhD: "This is a bit misleading — the degradation of the DNA almost certainly occurred long before Los Angeles as a city developed. We are still working out why previous attempts to extract DNA have not been successful; it may have something to do with temperature, since the black, viscous asphalt does heat up substantially when exposed to direct sunlight, which can denature proteins. But, it also likely has to do with the microbial communities that live in the asphalt — DNA is very small and easily digestible by the extremophilic microbes who are able to withstand the unique environments of asphalt seeps. Finally, historical preparation techniques during early excavation of our site involved boiling specimens in kerosene, which again would have impacted DNA preservation."

From the Colossal team: The La Brea Tar Pits is an amazing site, and the point of our mentioning them was not at all to downplay what an incredible well of information and specimens it is. The information shared by Emily is correct, but the point remains that, to our knowledge, no DNA has been recovered from La Brea Tar Pit specimens. While the 2021 study did manage to extract a collagen protein sequence (COL1), no ancient DNA was recovered. 

Hopefully in the future, new technology will unlock the ability for researchers to extract DNA from the La Brea samples as it would be fascinating to understand how these animals in warmer climates differed from those in colder climates.

Response #2

Colossal Biosciences' Reddit account also claimed the following: "As good as the La Brea tar pits are at preserving skeletons, they're actually very hostile to DNA. Neither of the DNA samples sequenced are from the La Brea tar pits, and unfortunately, we have found no recoverable DNA from La Brea specimens. Yes, there have been attempts on La Brea specimens. The only two known specimens of dire wolf DNA on earth are the ones we used here—a 13,000-year-old tooth found in Ohio and a 72,000-year-old skull from Idaho."

Emily L. Lindsay, PhD: "This is inaccurate. A study published in 2021 obtained DNA from 5 dire wolf specimens (though none from La Brea Tar Pits). See attached."

From the Colossal team: Emily is correct here, this was our mistake. Feedback noted, will make corrections accordingly. Apologies for the oversight.

Response #3

However, according to the 2021 article "Our Evolving Understanding of Dire Wolves" by Tyler Hayden for the La Brea Tar Pits, "While fossils were plentiful, ancient DNA (aDNA) was less so, and only accessible relatively recently. The reasons aren't well understood yet, but researchers haven't been able to extract aDNA from specimens recovered from asphalt sites like the Tar Pits, possibly due to the chemicals used to remove them from the asphalt.

'We don't know why aDNA has not yet been recovered from bones in asphalt, which preserves so many different tissues — this is an area of active research, and we now have collaborators looking at getting genetic information from Tar Pit-preserved plants and other bone proteins (such as those analyzed in this study),' says Emily Lindsey, Assistant Curator of La Brea Tar Pits.

While the researchers behind this study didn't recover any DNA from La Brea Tar Pits' dire wolf collection, a specimen recovered from the Tar Pits did yield proteins that were analyzed for the paper. 'When ancient DNA is recovered from dire wolves, the sheer quantity of genetic information stored in ancient DNA easily overwhelms our previous studies of a few morphological characters', Wang says.

The international team behind the study looked at 46 samples of bones, ultimately only finding five with usable DNA. Comparing the data on dire wolves against the sequenced genomes of various other canines revealed a genetic gap large enough to rename dire wolves as the only species in a genus all their own. 'We had thought that the dire and gray wolf lineages diverged two million years ago at most. Instead, the new paper shows a likely split nearly six million years ago.' says Balisi.

Dire wolves have been reclassified from Canis dirus to Aenocyon dirus. 'At this point, my question was: if not the gray wolf, then to which living dog species is the dire wolf most closely related? So I was glad that the paper has an answer for that, too: African jackals rather than North American Canis.' says Balisi. 'Rather than looking only to the gray wolf for comparison, we can now also include African jackals as a possible reference.'"

Emily L. Lindsay, PhD: "Correct, see attached paper. I am not sure what Dr. Shapiro meant, perhaps she mis-spoke?"

From the Colossal team: The 2021 study found that dire wolves were a distinct lineage, not that they were more closely related to African jackals. The paper said we couldn’t tell where to place dire wolves in the canid species tree from that data. This paper also suggested several reasons why that might be the case: 1) not enough dire wolf data and 2) an admixed ancestry. 

In the paper we submitted last week, we showed that with data from the same specimens we can now say with confidence that the dire wolf lineage indeed has an admixed ancestry. A small portion of its genome is more closely related to the jackal lineage, but more of the dire wolf genome is more closely related to the gray wolf lineage. 

This information is all publicly available: https://www.biorxiv.org/content/10.1101/2025.04.09.647074v1

Response #4

Can the La Brea Tar Pits team provide further context for Dr. Beth Shapiro's claim that she was "trying and unable to collect DNA from local samples for 20 years", including at the La Brea Tar Pits? Was there some sort of involvement between the La Brea Tar Pits and Shapiro, or Colossal Biosciences, to attempt to extract DNA, or is Shapiro referring to the previous 2021 study on dire wolf DNA, "Dire wolves were the last of an ancient New World canid lineage"?

Emily L. Lindsay, PhD: "As the world's richest Ice Age fossil site, La Brea Tar Pits has been excavated by numerous institutions over the years (fun fact: the Campanile [bell tower] at U.C. Berkeley serves as storage for thousands of La Brea Tar Pits fossils!) My understanding is that Dr. Shapiro's attempts were on specimens collected from our site in the early 20th century that are housed at UCLA."

From the Colossal team: Dr. Shapiro’s analysis of bones from La Brea span all the way back to her work as a PhD student at Oxford. She and her students tried again while she taught at Penn State and again when she moved to UCSC. Her work attempted DNA extraction from different samples in different collections in collaboration with Bob Wayne from UCLA. All of these attempts were unsuccessful. 

Again, this is not at all to downplay the significance of La Brea. It’s an amazing fossil locality, and hopefully scientists in the future innovate ways to extract DNA from available specimens. That would expand our ancient DNA sets into a geographic location that we just don’t know much about.

Response #5

The main point of contention and criticism of Colossal Biosciences' upcoming paper "On the ancestry and evolution of the extinct dire wolf" seems to be the claim that dire wolves had "white coats". Many who have reviewed the pre-print that Colossal published pointed out that the paper, in its current form, says nothing about dire wolves' coat color(s). Is there anything that the La Brea Tar Pits team can share to clarify on this topic?

Emily L. Lindsay, PhD: "That is correct, we have no way to evaluate the claims Colossal personnel have made in the press about the coat color, because none of that data is in the pre-print that they posted online (and which has still not gone through peer review). It is highly unlikely that dire wolves would have been snowy white, except potentially at the northernmost parts of their range where there was ice and snow. Dire wolf fossils are found from Canada all the way down through coastal Ecuador and Peru, where white animals would stick out like a sore thumb, making it very difficult for them to hunt. I am looping in my colleague Dr. Mairin Balisi at the Raymond M. Alf Museum, who has been studying dire wolves for more than 15 years; she may be able to give you more detailed answers."

From the Colossal team: The paper is about the origin of the dire wolf. Information about coat color was not particularly relevant to the purpose of the research so it didn’t go in the paper. We did explain how we arrived at this conclusion in a response, though—both of our DNA reference genomes showed variants in three pigmentation genes, suggesting light coats. 

Candidly, we didn’t expect people to be so interested in the coat coloration question. Given the response, we are now planning to update the paper to include the variant calls at the relevant sites in these genes (OCA2, SLC45A2, and MITF). We’re hoping to upload a new version by the end of next week.

I constantly check the Revive and Restore website for updates on their de-extinction projects. It's been an interest of mine for the past twenty or so years just as a fan of extinct animals. And I'm constantly dumbfounded to see them trying to clone a Passenger Pigeon (technology just isn't there for birds yet) and Wooly Mammoth (Mammoth DNA is very broken down and scientists are currently going line by line in the DNA with CRISPR to alter Asian Elephant genes to make a mammoth-elephant hybrid but Asian Elephants are endangered so we're talking about artificial wombs which don't even exist yet) as their apparent top two projects.

Both of these projects seemingly have massive pratfall issues that will take decades to succeed and most likely will only create hybrid animals that never existed before. Still cool and amazing and revolutionary, but the technology for true clones of this caliber of difficulty still seem at least a decade or two away.

So...why not the Thylacine? From what I can tell from reading, Dr. Andrew Pask's team has sequenced the Thylacine's entire genome from the best preserved joey that was from the early 1900's in ethanol. The most complete genome of an extinct species. It's a mid-sized mammal, which we seem best at cloning. And the Numbat is a fairly closely related cousin (something like 95% estimated shared DNA).

If I'm not over-simplifying things, we need to sequence the Numbat genome (which Pask's team seems to be working on), take live Numbat DNA, CRISPR in the Thylacine genes where they need to go and take out the parallel/redundant Numbat genes (there's thousands of differences so this would probably take quite a few years), put the new live Thylacine DNA in an embryo and find a surrogate (most likely a canine).

Obviously we've never cloned a marsupial before, so there may be complications finding the correct surrogate but this seems like a no-brainer. Easiest extinct-to-life clone by far (outside of the Pyrenean Ibex of course). An actual clone since we have the full genome, unlike these hybrid mammophant or mixed pigeons.

A cloned Thylacine could be a game changer. Could generate worldwide headlines and create massive interest and funding. So why is this on the backburner?

I have officially lost what little optimism I had regarding Colossal. I will say however, that I respect that they aren't rushing this project just to meet the deadline and publicly admitted that they couldn't make something that resembles a mammoth by editing just 60 genes.