10 extinct species that are genetically still alive
Neanderthals have been extinct for thousands of years, but roughly 1 to 4% of their DNA lives on in modern Eurasian populations. This is not a rare case; long-gone species continue to return in many modern creatures. Thanks to the miracle of evolution and inheritance, the ghosts of the cave bear, the aurochs and various mysterious ancestors still walk among us.
Related: Top 10 Amazing Uses of Genetic Technology
10 Wild cannabis / modern cannabis
For a long time, scientists could not find the birthplace of cannabis and speculated that it was probably Central Asia. In 2021, a study tackled the monumental task of discovering the origins of cannabis. What made it so difficult was the fact that humans have selectively bred numerous species for thousands of years, obscuring the lineage back to the original ancestor plant.
The research yielded unexpected findings. After sequencing more than 100 cannabis genomes, it turned out that the plants evolved in China, not Central Asia. The biggest surprise, however, was an unknown cannabis line.
The team expected to see the two known types: the hemp plant grown for its fiber and the cannabis grown for the production of cannabinoids. The new line was wild cannabis (human-engineered strains that returned to nature). The wild plants were more closely related to the wild ancestor than any living variety. The study also concluded that this ancestral species is likely extinct.[1]
9 Ghost Lineage / Sub-Saharan Populations
In 2017, scientists examined human saliva. They wanted to know more about a certain protein that makes saliva slimy. It's called mucin-7 and also traps microbes, possibly to prevent harmful organisms from entering the body. However, the research came up with a surprise.
To properly analyze the protein, researchers took samples from more than 2,500 modern human genomes. They looked into the gene for mucin-7, called MUC7, when they discovered that a large number of people from sub-Saharan Africa had a very different version of the MUC7 gene. Upon further investigation, it turned out that it came from an unknown extinct human species or a 'spirit lineage'.
The unusual gene is all that remains of this mysterious human species today, as no fossils exist. It is estimated that the ancestors of modern humans encountered and intermingled with this unknown group about 200,000 years ago.[2]
8 The Aurochs/Texas Longhorn Cattle
In 2013, the University of Texas published a family report on the Texas Longhorn. Ancient wisdom held that these cattle came from a purely European lineage. However, the Longhorn's heritage turned out to be more global.
Genetic markers from 58 cattle breeds were examined, showing that 85% of Longhorn DNA was 'taurine'. This group was descended from the aurochs, a now extinct wild ox. The aurochs lived in Europe, but taurine animals were domesticated in the Middle East several millennia ago. The remaining Longhorn DNA was 'indicine', descendants of the aurochs that were domesticated in India before spreading to Africa and the Iberian Peninsula.
The direct ancestors of the Texas Longhorn were brought to America by Christopher Columbus. They were feral for centuries and regained a wild appearance reminiscent of the aurochs. Some ranchers came to appreciate the Longhorn's independence and ability to withstand harsh conditions, and they once again became livestock.[3]
7 Cave bears / Brown bears
The giant cave bear became extinct about 25,000 years ago. Recently, researchers have been extracting DNA from cave bear fossils and comparing them to brown bears. To their surprise, they discovered that modern brown bears carry between 0.9 and 2.4% cave bear DNA.
The discovery was unexpected for two reasons. First of all, cave bears and brown bears are two very different species. For example, cave bears were herbivores, while brown bears are carnivores. Second, cave bears were huge. Males can weigh up to 1,000 kg, while male brown bears average about 300 kg. How the two species came to romance each other, given their size difference, remains a good question.
It's no mystery how this was even possible. Before cave bears disappeared, they lived with brown bears, and this gave them the opportunity to pass on their genes. Interestingly, Alaskan brown bears carry the smallest amount of cave bear DNA, while European brown bears have the most.[4]
6 Denisovans/Tibetans
Denisovans were a mysterious humanoid species known only from a few bones and their genome. Denisovan DNA lives on in several modern groups, including Han Chinese, Tibetans and Melanesians. But there is something special about the Denisovan heritage of Tibetans.
Everyone has a gene called EPAS1. Whenever the oxygen level in the blood drops, the production of extra hemoglobin is triggered, increasing the oxygen-carrying capacity of the blood. At low altitude everything runs smoothly. The higher one goes and the thinner the air becomes, the harder EPAS1 has to work – and the results are deadly.
As EPAS1 increases hemoglobin to cope with increasingly less oxygen-rich conditions, the blood thickens, leading to high blood pressure and heart attacks. Such dangers prevail above 3,962 meters, but most Tibetans can pass this point without difficulty. Their EPAS1 gene, inherited from Denisovans, does not go into overdrive at higher altitudes. It only slightly increases hemoglobin, allowing Tibetans to climb higher without the side effects seen in others.[5]
5 Mysterious Wolf/Dogs
The origin of dogs has always been a mystery. It's not as simple as taking a DNA sample and seeing the wolf that turned into a dog. Domestic canines appeared as early as 33,000 years ago. They continued to interbreed with wolves, clouding the genetic identity of the first species to evolve into dogs.
To avoid this later tangle of wolf DNA, researchers sequenced the genomes of two dog breeds whose territories have not overlapped with wolves for thousands of years. These were the Australian Dingo and the African Basenji. The study predicted that their genetics would match a wolf species native to Asia, the Middle East or Eastern Europe, the three areas thought to be the most likely locations for dog domestication.
Surprisingly, the tests showed that dogs and modern wolves are sister groups and not ancestors and descendants. In other words, dogs are not from the same lineage as modern wolves. This pointed to an unknown, extinct species of wolf that left no descendants other than dogs.[6]
4 Giant Pinta Tortoise / Hybrid Galápagos Tortoise
The last Giant Pinta tortoise died in 2012. During his lifetime, 'Lonesome George' was known as the last of his kind. When he died in captivity, he was over a hundred years old.
The Pinta Giant Tortoise was one of fifteen species of tortoise that once roamed the Galápagos Islands. In 2020, researchers visited one of the islands, Isabela Island, and found a female turtle. Tests revealed that she was a hybrid carrying the genes of the Pinta giant tortoise. But this was just the beginning. The team also found 29 turtles with partial ancestors of Floreana giant tortoises, an extinct species from Floreana Island, another location in the Galápagos chain.
All hybrids were transferred to a breeding center. The Floreana group offers hope that this species will be revived (to some extent). To ensure the preservation of Lonesome George's lineage, scientists are now actively searching for more Pinta hybrids on the islands.[7]
3 Red Wolf/Galveston Island Dogs
Red wolves were once common in the southeastern United States. However, hunting and habitat loss destroyed the species. By the time conservation efforts began in the 1970s, it was too late – at least for the wild population. While several dozen animals were kept in breeding programs, the red wolf was declared extinct in the wild in 1980.
On Galveston Island, Texas, coyote-like dogs sparked rumors that the wild red wolf was alive and well. Genetic experts have received many samples of “red wolves” in the past, and most of them turned out to be coyotes. That changed a few years ago when the island's traffic fatalities were sent to a laboratory. The dogs were tested and two surprises emerged.
The first discovery was that the Galveston dogs were indeed genetically more similar to captive red wolves than to coyotes. This was already an exciting moment, but the second discovery was astonishing. The island animals still carried a gene from the original, pure red wolves that no longer exist in the captive population.[8]
2 Two extinct frogs / African clawed frog
The African clawed frog won't win any beauty contests, but genetically speaking this amphibian is a wonder. The creature contains the remains of not one extinct animal, but two. Researchers simply call these ancestors S and L.
This pair bounced around millions of years ago and their origin story is just as interesting. Basically, an older frog species split in two to become S and L. Millions of years later, the two species began interbreeding, and slowly became one frog again: the African clawed frog.
As a result of this interesting backstory, the DNA of the African clawed frog is highly unusual. The frog has two complete, different sets of chromosomes: one from S and one from L. This inheritance doubled the entire genome of the animal, which is extremely rare.[9]
1 Quagga/plains zebra
In almost all cases where the genes of an extinct animal survive in another species, the genetic material was passed on through hybridization or evolution. But that is not the case with the Quagga and the Plains Zebra.
Zebras are known for their stripes. The Quagga also had solid stripes, but only on their necks. The rest of their bodies showed faded stripes that gave way to brown or white hindquarters. In 1883, the last Quagga died in a zoo and the species was declared extinct.
Then a shocking discovery changed things. Reinhold Rau, from the University of Cape Town, found that Quagga DNA was identical to Plains Zebra DNA. The Quagga was not a separate species, as previously thought; it was a subspecies of the surviving Plains Zebra.
Rau founded the Quagga Project, where plains zebras with Quagga-like traits were selectively bred to recreate the animals lost in the 19th century. The project is still ongoing and has produced a herd of zebras that are, genetically and in appearance, true Quaggas.[10]