DNA offers sharper image of ancient humans

Scientists have produced a digital image of a genome tens of thousands of years old with the resolution of a typical living person’s, enabling them to describe the life and history of the ancient humans in great detail, they reported in Thursday’s issue of Science magazine.

Led by Svante Paabo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, the scientists have created the highest quality genome sequence of ancient humans yet.

Therefore, the Denisovans — as the group has been called, after the Siberian cave harboring its fossils: a finger bone and two teeth — are much better known genetically than Neanderthals, although there are hundreds of specimens from them.

“There is no difference in what we can learn genetically about a person that lived 50,000 years ago and from a person today,” Paabo said Wednesday in a conference call with reporters.

The international team of researchers used only genetic material from a tiny finger bone from a girl that lived in Siberia tens of thousands of years ago. The specimen was found in a cave in 2008 and, based on preliminary genetical analyses by the team in 2010, was attributed to a novel group of humans closely related to Neanderthals.

“The Denisovan genome is particularly close to my heart, because it was the first time that a new group of humans were discovered and defined just from DNA,” Paabo said.

The scientists owe their insights mainly to new technological advances in sequencing of prehistoric DNA. “All forensics on ancient DNA were originally developed for modern DNA,” said Matthias Meyer of the Max Planck Institute, lead author of the article. He was responsible for developing approaches that take into account challenges typical for ancient genetic material, such as its scarcity and degraded state.

The breakthrough came partly through starting the sequencing with single strands of DNA, as opposed to the usual approach of using double strands. Earlier this year, the researchers made the raw genome sequence available to the public by publishing it online.

Using the DNA alone, the scientists reconstructed the appearance of the Siberian girl: She had brown eyes and dark hair and skin. Also from genetic information, the scientists pieced together the girl’s pedigree and compared it with modern humans’ and Neanderthals’. The Denisovans contributed genetic material only to present Australian Aborigines and some people in Melanesia, whereas Neanderthals left their mark on everyone outside Africa, Paabo said.

The scientists analyzed the differences between the DNA of the Denisovan and that of modern humans around the world, allowing them to come up with an estimate of the specimen’s age. Based on the mutation rate in modern humans, the team approximated the age of the Siberian girl at about 80,000 years. That conflicts with archeological data that assign the geological layer of the fossil to an age of 30,000 to 50,000 years. Carbon dating, a standard procedure to determine the age of fossils, would provide a more definitive answer, but the specimen is too small for that.

“It is amazing that we can sequence the whole genome, but there is too little carbon to date it,” Paabo said.

The scientists estimated that the Denisovans split from modern humans between 700,000 and 200,000 years ago, a broad range attributed to uncertainties about the underlying mutation rates.

The researchers also inferred the population sizes of the ancient Denisovans based on the differences between genes from the father and the mother in the Siberian girl’s DNA. Because the genes are very similar to each other, the scientists estimated the genetic diversity and therefore the population size to have been low, although the Denisovans have occupied large parts of Asia.

Paabo shied away from calling the Denisovans a separate species, because they interbred with the ancestors of modern humans. “I wouldn’t call Neanderthals a different species from humans, either. I stay away from that debate,” he added.

The scientists speculated that a single population moving out of Africa gave rise to the Denisovans and Neanderthals. The new findings support the notion that the ancestors of modern humans mixed with groups of ancient humans, instead of quickly replacing them.

As a next step, the scientists plan to re-sequence the Neanderthal using the new methods and get it on par with the genome of the Siberian girl.

Talk to us

> Give us your news tips.

> Send us a letter to the editor.

> More Herald contact information.

More in Local News

A firefighter stands in silence before a panel bearing the names of L. John Regelbrugge and Kris Regelbrugge during the ten-year remembrance of the Oso landslide on Friday, March 22, 2024, at the Oso Landslide Memorial in Oso, Washington. (Ryan Berry / The Herald)
‘Flood of emotions’ as Oso Landslide Memorial opens on 10th anniversary

Friends, family and first responders held a moment of silence at 10:37 a.m. at the new 2-acre memorial off Highway 530.

Julie Petersen poses for a photo with images of her sister Christina Jefferds and Jefferds’ grand daughter Sanoah Violet Huestis next to a memorial for Sanoah at her home on March 20, 2024 in Arlington, Washington. Peterson wears her sister’s favorite color and one of her bangles. (Annie Barker / The Herald)
‘It just all came down’: An oral history of the Oso mudslide

Ten years later, The Daily Herald spoke with dozens of people — first responders, family, survivors — touched by the deadliest slide in U.S. history.

Victims of the Oso mudslide on March 22, 2014. (Courtesy photos)
Remembering the 43 lives lost in the Oso mudslide

The slide wiped out a neighborhood along Highway 530 in 2014. “Even though you feel like you’re alone in your grief, you’re really not.”

Director Lucia Schmit, right, and Deputy Director Dara Salmon inside the Snohomish County Department of Emergency Management on Friday, March 8, 2024, in Everett, Washington. (Ryan Berry / The Herald)
How Oso slide changed local emergency response ‘on virtually every level’

“In a decade, we have just really, really advanced,” through hard-earned lessons applied to the pandemic, floods and opioids.

Ron and Gail Thompson at their home on Monday, March 4, 2024 in Oso, Washington. (Olivia Vanni / The Herald)
In shadow of scarred Oso hillside, mudslide’s wounds still feel fresh

Locals reflected on living with grief and finding meaning in the wake of a catastrophe “nothing like you can ever imagine” in 2014.

Everett mall renderings from Brixton Capital. (Photo provided by the City of Everett)
Topgolf at the Everett Mall? Mayor’s hint still unconfirmed

After Cassie Franklin’s annual address, rumors circled about what “top” entertainment tenant could be landing at Everett Mall.

Everett
Everett man sentenced to 3 years of probation for mutilating animals

In 2022, neighbors reported Blayne Perez, 35, was shooting and torturing wildlife in north Everett.

The Washington State University Snohomish County Extension building at McCollum Park is located in an area Snohomish County is considering for the location of the Farm and Food Center on Thursday, March 28, 2024 in Everett, Washington. (Olivia Vanni / The Herald)
Year-round indoor farmers market inches closer to reality near Mill Creek

The Snohomish County Farm and Food Center received $5 million in federal funding. The county hopes to begin building in 2026.

Dorothy Crossman rides up on her bike to turn in her ballot  on Tuesday, Aug. 1, 2023 in Everett, Washington. (Olivia Vanni / The Herald)
Everett leaders plan to ask voters for property tax increase

City officials will spend weeks hammering out details of a ballot measure, as Everett faces a $12.6 million deficit.

Starbucks employee Zach Gabelein outside of the Mill Creek location where he works on Friday, Feb. 23, 2024 in Mill Creek, Washington. (Olivia Vanni / The Herald)
Mill Creek Starbucks votes 21-1 to form union

“We obviously are kind of on the high of that win,” store bargaining delegate Zach Gabelein said.

Lynnwood police respond to a collision on highway 99 at 176 street SW. (Photo provided by Lynnwood Police)
Police: Teen in stolen car flees cops, causes crash in Lynnwood

The crash blocked traffic for over an hour at 176th Street SW. The boy, 16, was arrested on felony warrants.

The view of Mountain Loop Mine out the window of a second floor classroom at Fairmount Elementary on Wednesday, Jan. 10, 2024 in Everett, Washington. (Olivia Vanni / The Herald)
County: Everett mining yard violated order to halt work next to school

At least 10 reports accused OMA Construction of violating a stop-work order next to Fairmount Elementary. A judge will hear the case.

Support local journalism

If you value local news, make a gift now to support the trusted journalism you get in The Daily Herald. Donations processed in this system are not tax deductible.