Ancient virus that spared humans may explain brain divergence from chimps

Also: crows make ultrafast decisions, a medieval monk recycled a Roman sarcophagus, and Van Gogh's Starry Night matches a specific date.

By LineZotpaper AI staff

Published24 October 2026

Read Time3 min

A family of retroviruses that infected the ancestors of chimpanzees, bonobos and gorillas millions of years ago but spared humans may have helped drive the divergence of human and chimpanzee brain development, according to a study published in Science Advances.

Researchers from Lund University and other institutions discovered that retroviral insertions called PTERV1, which are abundant in chimpanzees but absent in humans, silence a gene called LINC00662 in chimps. In humans, that gene remains active during brain development and influences neuronal maturation, development and outgrowth.

Using human and chimpanzee brain organoids, miniature clusters of neurons grown from stem cells, the team found that the chimpanzee-specific insertions on chromosome 19 suppress LINC00662. “Among primates, the human brain stands out as the largest and most complex due in part to an increase in cortical neurons and increase in synaptic connectivity,” the researchers said, noting that the human brain is about three times the size of the chimpanzee brain.

The PTERV1 insertions are thought to have originated from infections in the ancestors of African apes about 5 to 7 million years ago. The absence of these insertions from the human genome suggests that either the human and chimpanzee lineages did not occupy the same habitat at the time, or that germline-competent cells of the human ancestor were resistant to the infection.

In a separate study from the University of Tübingen published in Science, researchers found that carrion crows can make ultrafast decisions in about 235 milliseconds on average, roughly twice as fast as observed in monkeys or humans, without sacrificing accuracy. The crows performed a visual discrimination task by pecking a touchscreen to select the predominant direction of moving dots, achieving about 75 percent accuracy.

At Westminster Abbey, archaeologists may have solved the mystery of a Roman sarcophagus first unearthed on the abbey grounds more than 200 years ago. Despite an inscription identifying the occupant as Valerius Amandinus, a wealthy Londoner from 300–400 AD, radiocarbon dating of the bones found inside suggests they belong to a medieval monk named Ælfwig, born in 993. Study author Rodwell Warwick of Westminster Abbey argues the burial likely belonged to Abbot Ælfwig, with the sarcophagus recycled centuries later.

Finally, a team has proposed that the celestial elements of Vincent van Gogh's "The Starry Night" match the sky over Provence on July 22, 1889, when the waning-crescent Moon, Venus and the Hyades would have appeared as depicted. The findings were published in Scientific Reports.

Analysis

Why This Matters

The study offers a concrete mechanism, retroviral insertions affecting a specific gene, by which ancient infections may have contributed to human brain evolution, shedding light on the genetic basis of human cognitive complexity.
The finding underscores that evolutionary divergence can result from chance events, such as early humans simply not being in the same place as the virus.
The other studies provide insights into avian decision-making efficiency, historical reuse of ancient artifacts, and the realism of a famous artwork.

Background

Retroviruses are infectious agents that can invade the genomes of their hosts and insert copies of their own genetic material, producing long-term evolutionary effects. Endogenous retroviruses are remnants of past infections that have become inherited parts of the genome. Brain organoids are miniature brain-like structures grown from stem cells that can model aspects of brain development. The Westminster Abbey sarcophagus was exhumed during King Henry III's reconstruction in the mid-1200s and remained in a courtyard for centuries before being broken open in 1820.

What to Watch

Further research into whether other endogenous retroviral insertions influence brain development in primates, and whether the LINC00662 gene plays a role in human-specific cognitive traits.
Ongoing investigations at Westminster Abbey into the original occupant Valerius Amandinus, whose remains have not been accounted for.
Follow-up studies on avian decision-making circuits and their evolutionary pressures for rapid visuomotor control.

Sources

An Ancient Virus Explains Why the Human Brain Is Special · 404 Media

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11 claims in this story checked against 1 source: 7 supported.

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SupportedThe headline says an ancient virus that spared humans may explain divergence between human and chimpanzee brains.404 Media: “A virus that infected chimpanzees millions of years ago shaped the divergence of human and chimp brain development”
SupportedThe opening says PTERV1 infected the ancestors of African apes millions of years ago but is absent from humans, and may have contributed to human–chimpanzee brain divergence.404 Media: ““These PTERV1 insertions are thought to have originated from infections that occurred in the ancestors of African apes about 5 to 7 million years ago,” said the team. “PTERV1 elements are found in chimpanzees, bonobos, and gorillas…Notably, the absence of PTERV1 insertions from the human genome”
Partly supportedResearchers from Lund University and other institutions discovered the PTERV1 mechanism.404 Media: “said a team led by researchers from Lund University”
SupportedThe researchers said, “Among primates, the human brain stands out as the largest and most complex due in part to an increase in cortical neurons and increase in synaptic connectivity,”404 Media: ““Among primates, the human brain stands out as the largest and most complex due in part to an increase in cortical neurons and increase in synaptic connectivity,” said a team led by researchers from Lund University.”
SupportedThe human brain is about three times the size of the chimpanzee brain.404 Media: ““With a size roughly three times that of our closest living evolutionary relative, the chimpanzee, it has unique cognitive capabilities.””
SupportedCarrion crows make decisions in about 235 milliseconds on average, roughly twice as fast as monkeys or humans, without sacrificing accuracy.404 Media: ““approximately 235 milliseconds on average, which is roughly twice as fast as has been observed in monkeys or humans and without sacrificing accuracy,” according to a new study.”
SupportedThe crows achieved about 75 percent accuracy on the visual discrimination task.404 Media: “The crows performed the task dozens of times at extremely high speeds, achieving an overall choice accuracy of 75 percent (crow 1) and 73 percent (crow 2).”
Partly supportedThe summary says a medieval monk recycled a Roman sarcophagus.404 Media: ““The corpse had been laid in a timber coffin and covered with lime; it was then placed inside the sarcophagus.””
Partly supportedRadiocarbon dating of the bones suggests they belonged to Ælfwig, born in 993.404 Media: ““The burial was of a male, probably in his late forties, and was radiocarbon dated to around the turn of the 11th century,” said study author Rodwell Warwick of Westminster Abbey. “It is argued that this was the prestigious burial of Abbot Ælfwig.””
Partly supportedThe summary says Van Gogh’s Starry Night matches a specific date, without qualifying that this is a proposal.404 Media: “Now, a team has proposed that the celestial elements of the painting match with a specific night—July 22, 1889—when “the waning-crescent Moon, Venus, and the Hyades cluster gather within that narrow frame,” according to a new study.”
SupportedA team proposed that the celestial elements in Starry Night match the sky over Provence on July 22, 1889.404 Media: “Now, a team has proposed that the celestial elements of the painting match with a specific night—July 22, 1889—when “the waning-crescent Moon, Venus, and the Hyades cluster gather within that narrow frame,” according to a new study.”