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What’s in a ‘species’? Discussing the Colossal Dire Wolf

April 25, 2025

April 2025. Did Colossal bring back the dire wolf?

Short answer, not really.

The long answer is a bit more complicated and goes into what ‘species’ actually means.

Earlier in April, the biotech company Colossal put out a press release announcing the first de-extinction. They’ve genetically engineered a dire wolf out of extinction—and now, for the first time in 10,000 years, they’re back in their natural habitat (or so Colossal says).

De-extinction is the process of bringing back extinct species, or modern-day analogs to extinct species. This can be done through cloning DNA from preserved specimens or by gene editing their closest related surviving species to make them resemble their extinct kin. While this used to be an unlikely science-fiction dream, the development of CRISPR-Cas9 and other gene editing techniques has made it a possibility.

Colossal says their team used DNA sourced from a 13,000 year old tooth & 72,000 year old skull to analyze the dire wolf’s genome. They used this as the basis for their edits, which they carried out on three gray wolf embryos.

What is a species?

If you’ve taken a biology class, you’ve probably heard the term “species” tossed around before. The conventional definition of species is a group of organisms in which two individuals can reproduce & create fertile offspring. It’s generally a good rule of thumb definition, but there’s a lot of edge cases where the topic becomes muddy.

What happens when you look at critters that only reproduce asexually, like bacteria? What about cases where two species hybridize, and remain fertile?

These outlier cases have led some scientists to propose alternate definitions for species. Colossal’s Chief Science Officer (CSO) Beth Shapiro said in an interview with ABC:

“I think that the best definition of a species is if it looks like that species, if it is acting like that species, if it’s filling the role of that species then you’ve done it.”

This definition of species depends on its phenotype, behavior, and niche. A phenotype is a species’ physical expression of its genes. For instance, your eye color is a phenotype and is the observed effect of the genes behind your eye color. Shapiro said that their analysis of ancient dire wolf DNA suggested that they had light fur, which is why Colossal edited their gray wolf skins to be an eye-catching white. But instead of editing the pigment genes actually responsible for fur color, the team instead disabled two genes whose absence in dogs & other canids is known to cause a white coat. Colossal avoided the actual edits because they were linked to increased risks of deafness, blindness, and albinism—traits that the team didn’t want to take chances on.

What about behavior? Does the dire wolf behave like a real dire wolf? Well, they’ve been extinct for thousands of years, and we lack any actual evidence as to their behavior, so we can’t actually test that point.

What about their niche? A niche refers to the ecological role a species carries in its environment. For example, owls occupy the niche of eating small animals such as mice in woodland areas. The dire wolf was a carnivore that likely scavenged & hunted large megafauna. It was a species adapted for life in Pleistocene, and part of why it went extinct is thought to have been the extinction of its typical prey. If a dire wolf was to be de-extincted & rewilded today, it would be in unfamiliar territory—there are no more megaherbivores. Additionally, the three wolves Colossal has bred are living in a fenced-off lot and aren’t actively contributing to their environment.

Following Shapiro’s definition of a species, Colossal’s dire wolf checks the phenotype box but doesn’t meet the behavior/niche ones. Is that enough to consider it a species?

At the end of the day, the idea of what a species is is complicated. Ambiguity & argument around definitions like this can hold back science. This linguistic debate is no trifling matter—it can impact real world legislation and policy! For example, as soon as the news of Colossal’s ‘de-extinction’ broke, the Secretary of the Interior Doug Burgum tweeted out a statement suggesting that now that de-extinction technology is viable, the Endangered Species List is on the chopping block. De-extinction might be used to devalue the importance of conservation, instead shifting the mindset of preservation to one of “we can just bring them back!”

If you look at the news, you’ll notice a lot of the reporting around the Dire Wolf story focuses on the miracle of “listening to the howls of a dire wolf pup brought back from extinction for 10,000 years.” By focusing on the info that brings the best headline, science can sometimes be shifted out of focus.

Whenever new technologies come out, it’s important to approach them with a critical mind. What do you think defines a species? Do you think Colossal has revived the dire wolf?

Works Cited

https://www.technologyreview.com/2025/04/08/1114371/game-of-clones-colossals-new-wolves-are-cute-but-are-they-dire/

https://abcnews.go.com/US/dire-wolf-revived-biotech-companys-de-extinction-process/story?id=120558562

https://evolution.berkeley.edu/evolution-101/speciation/defining-a-species/

https://x.com/SecretaryBurgum/status/1909345951069651032

Picture credit Colossal

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  Timothy Durham was convicted of rape when a test showed his DNA genotype matched the DNA recovered from the crime scene. Eye witnesses testified that Durham was in a different state at the time of the incident, but he wasn’t exonerated from his 3000 year sentence until follow up DNA analysis showed that the preliminary forensic analysis used in the trial was misinterpreted (Thomas et al.). DNA testing serves an invaluable part in our criminal justice system, but it comes with complications and bias that can lead to wrongful convictions and misinformed juries.  

Background:

Forensic genetics aims to identify the origin of a biological sample. It can be traced back to Karl Landsteiner who discovered human ABO blood groups. With blood groups, suspects could be eliminated based on their blood type. For example, if a suspect had type A blood and there was type B blood left at the scene by the perpetrator, the investigators could rule out the suspect. Unfortunately, the reverse didn’t work. If the suspect and perpetrator both had the same blood type, it can’t be concluded that the suspect was guilty. Blood identifiers evolved into 8 distinct categories which improved the ability to eliminate suspects, but could only conclude that (if the system matched) it might be the perpetrator or this person might be related to the perpetrator (Jobling and Gill). The field evolved in the 1980s with the discovery of Minisatellites, lines of repetitive DNA that don’t encode proteins. Minisatellite patterns in DNA create what we know today as the DNA fingerprint, and it has a much higher accuracy rate than previous methods (Augustyn et al.). Around the same time, a breakthrough for victims of sexual assault was discovered. In the case of assault, bodily fluids of both the victim and the assaulter can get mixed. A process called differential lysis was created which could selectively increase the concentration of sperm in a fluid sample thereby allowing for accurate DNA testing (Jobling and Gill). Forensics evolved to use single-locus probe testing after several years because of its ease of interpretation. It looked at specific minisatellites that had high variability between subjects. This was the first DNA-based method to be used in a criminal investigation. Two murder homicides from several years apart were connected using DNA evidence. The evidence was then used to exonerate an innocent man, and the guilty party was found when he tried to evade mandatory DNA testing for all men in the small town. His guilt was then reinforced when the DNA profiles matched, and he gave a confession (Jobling and Gill). Finding DNA at a crime scene doesn’t guarantee that you’ll find a murderer. There are issues with non-pure samples and limited samples that make DNA work difficult, and accreditation of facilities and new techniques and take time (Jobling and Gill).  

Subjectivity of DNA Interpretation:

In a 2009 publication, the National Academy of Science discusses the possibility for subjective influence in lab based forensics. The interpretation bias happens in complex cases where, for example, there could be a mixture of DNA. A study published in 2011 looked specifically at this issue. A gang rape happened in Georgia, and the mixture in DNA from the case was used to prosecute one suspect after another suspect took a plea bargain to testify against him. With DNA mixtures, there are three possible conclusions: suspect excluded, suspect cannot be excluded, and inconclusive. If the suspect is excluded, it means that there’s little to no possibility that his DNA is part of the sample. If the suspect cannot be excluded, it means that there’s a possibility that his DNA is part of the sample. In the trial, the DNA examiners who knew the context of the case concluded that the suspect being prosecuted could not be excluded. The 2011 study gave the DNA evidence from this case and the DNA profiles of the suspects to 17 forensic examiners. These examiners had no context of the case, and they all worked independently. Of the 17, only 1 came to the same conclusion (suspect cannot be excluded) as the examiners who knew the context of the case. Twelve of the 17 concluded that the suspect who was prosecuted and convicted had no relation to the DNA found in the sample. Not only does this show that subjectivity occurs due to the context of the case, but the 17 examiners came up with different findings based on their past experiences meaning that not all DNA analysis is objective. Some organizations like the Scientific Working Group on DNA Analysis Methods say that quantitative statistical evidence should be presented with every categorical conclusion, but the US doesn’t require this (Dror and Hampikian).

False Positives:

There are two categories that cause wrongful identification in a DNA report: coincidental matches and false positives. Coincidental matches are DNA matches between two unrelated people. The probability of these matches is about 1 to 500,000 for white individuals and about 1 to 350,000 for black individuals. This small probability of coincidental matches makes people feel confident in DNA evidence. False positives, on the other hand, are matches between DNA and test DNA that result from issues in the forensics lab. There have been multiple cases of forensics labs accidentally switching victim and suspected rapist DNA which lead to convictions that were later overturned when the lab realized the error. There are also cases of misreading or misunderstanding a sample. In a case from 1993, a man was convicted of rape because someone interpreted a mixed sample of victim and perpetrator DNA as an individual sample. The conviction was again overturned. To prevent false convictions, retesting DNA is allowed, but it’s not an efficient solution. Many people are pushing for statistical information on the probability of false positives, so that the jurors can make accurate judgements based on DNA evidence (Thomas et al.).  

Conclusion:

DNA analysis is a useful tool for the criminal justice system, but subjectivity can be an issue in forensic testing. To combat wrongful convictions, there are organizations like The Innocence Project who use DNA testing to free the innocent, but reformed forensic testing standards should be put in place to prevent subjectivity and to ensure juries are correctly informed during trials. https://www.innocenceproject.org/    

Citation:

Augustyn , Adam, et al. “DNA Finerprinting.” Encyclopedia Britannica , 26 Apr. 2018, www.britannica.com/science/DNA-fingerprinting#ref153186. Dror, Itiel E., and Greg Hampikian. “Subjectivity and Bias in Forensic DNA Mixture Interpretation.” Science & Justice, vol. 51, no. 4, 2011, pp. 204–208., doi:10.1016/j.scijus.2011.08.004. Jobling, Mark A., and Peter Gill. “Encoded Evidence: DNA in Forensic Analysis.” Nature Reviews: Genetics, vol. 5, no. 10, Oct. 2004, pp. 739–751., doi:10.1038/nrg1455. Thompson, William C, et al. “How the Probability of a False Positive Affects the Value of DNA Evidence.” Journal of Forensic Sciences, vol. 48, no. 1, Jan. 2003, pp. 1–8., doi:10.1520/jfs2001171.