31,000-year-old burial holds world's oldest known identical twins

The twin infants' double burial was unearthed in Krems am Wachtberg, Austria.
The twin infants' double burial was unearthed in Krems am Wachtberg, Austria. (Image credit: OREA ÖAW)

An ancient grave in Austria may represent the oldest burial of twins on record, a new study finds.

The 31,000-year-old burial dates to the Upper Paleolithic (a period lasting from 40,000 to 10,000 years ago), also known as the Old Stone Age. One of the infants died shortly after childbirth, while his twin brother lived for about 50 days, or just over 7 weeks, according to analyses of both babies.

A third infant, a 3-month-old, interred in a burial about 5 feet (1.5 meters) away is likely their cousin, according to the research, published online Nov. 6 in the journal Communications Biology.

Related: Photos: 2 paleolithic boys were buried with fox teeth and spears

Researchers found the twins' oval-shaped burial at the archaeological site of Krems-Wachtberg, on the bank of the Danube River by the town center of Krems in 2005. The twin infants' remains were covered with ochre, a red pigment often used in ancient burials across the world. The double burial also contained 53 beads made out of mammoth ivory that were likely once threaded on a necklace, and a perforated fox incisor and three perforated mollusks, which were possibly necklace pendants, the researchers said. A mammoth shoulder blade placed over the burial protected the small bodies interred beneath it over the millennia. 

The nearby burial of the other infant also contained ochre, as well as a 3-inch-long (8 centimeters) mammoth-ivory pin, which may have fastened a leather garment together at the time of burial, the researchers said.

The finding made headlines shortly after its discovery, and researchers even created a replica of the twins' burial, which went on display at the Natural History Museum Vienna in 2013. However, scientists still had much to learn about the ancient burial. So, in the new project, an interdisciplinary group of researchers teamed up to decipher the relationship between these three infants and to determine their sex and age at death. 

The study is the first on record to use ancient DNA to confirm twins in the archaeological record, the researchers said. And not just any twins, but identical twins

This is the "earliest proof of a twin birth," study senior researcher Ron Pinhasi, an associate professor in the Department of Evolutionary Biology at the University of Vienna, said in a statement (translated from German with Google Translate). Researchers don't know how common twin births were during the Upper Paleolithic (the rate fluctuates by region and time), but today, twins (both identical and fraternal) happen in about one in 85 births, while identical twins are born in about one in 250 births.

"To discover a multiple burial from the Paleolithic period is a specialty in itself," study lead researcher Maria Teschler-Nicola, a biologist at the Natural History Museum Vienna, said in the statement. "The fact that sufficient and high-quality old DNA could be extracted from the fragile child's skeletal remains for a genome analysis exceeded all of our expectations and can be compared to a lottery ticket."

A genetic analysis of the third infant revealed that he was a third-degree male relative, likely a cousin, the researchers found.

Related: Back to the Stone Age: 17 key milestones in Paleolithic life 

To determine at what age the babies died, the researchers looked at each baby's top second incisor. The team paid special attention to the so-called "newborn line," a dark line in the tooth enamel that separates the enamel formed prenatally from that formed after birth, Teschler-Nicola said.

Those newborn lines, as well the infants' skeletal development, suggested the twins were either full, or nearly full-term, babies. It appears that the infants' hunter-gatherer group buried the first twin, then reopened the grave when they buried his brother.

This finding confirms the cultural-historical practice of reopening a grave for the purpose of reburial, which had never been documented before in a Paleolithic burial, the researchers said.

The team also analyzed chemical elements, including isotopes of carbon, nitrogen and barium, in the tooth enamel, revealing that each of the twins was breastfed. Even though the twins' cousin survived for three months, "stress lines" in his teeth suggest that he had feeding difficulties, perhaps because his mother had a painful breast infection known as mastitis, or maybe because she didn't survive the birth.

It's unknown exactly why these infants died, but the deaths of these twins and their cousin were likely painful events for this Paleolithic hunter-gatherer group, who set up camp and buried their babies by the Danube so long ago. "The babies were obviously of particular importance to the group and highly respected and esteemed," Teschler-Nicola told Live Science. The extraordinary burials "seems to imply that the death of the babies was a great loss for the community and their survival."

Originally published on Live Science.

Laura Geggel

Laura is the archaeology and Life's Little Mysteries editor at Live Science. She also reports on general science, including paleontology. Her work has appeared in The New York Times, Scholastic, Popular Science and Spectrum, a site on autism research. She has won multiple awards from the Society of Professional Journalists and the Washington Newspaper Publishers Association for her reporting at a weekly newspaper near Seattle. Laura holds a bachelor's degree in English literature and psychology from Washington University in St. Louis and a master's degree in science writing from NYU.

  • Snorrie
    Given the time frame, is there any DNA or environmental evidence for a connection to Neanderthals and possibly their extinction?
  • TorbjornLarsson
    Snorrie said:
    Given the time frame, is there any DNA or environmental evidence for a connection to Neanderthals and possibly their extinction?

    Good question!

    The article claims they got DNA, so any signs of Neanderthal introgression could potentially be found.

    We were able to obtain
    well-preserved endogenous DNA from a cranial vault fragment
    of ind3, the results of which have already been published24.
    In the case of ind1 and ind2, we sampled their petrous bones.
    After enriching for 1,240,000 single-nucleotide polymorphisms
    (SNPs), we obtained 722,470 SNPs on chromosomes 1–22
    (1.772× average coverage) for ind1 by pooling data from two nonUDG-treated libraries (each SNP with a coverage of at least one
    sequence) (Table 1 and Supplementary Data 1). We recovered
    264,795 SNPs (0.282× coverage) for ind2 by pooling data from
    four UDG-treated libraries (Table 1 and Supplementary Data 1).
    Both individuals in Burial 1 were consistent with being genetic
    males based on the ratio of sequenced reads aligning to the X
    and Y chromosomes (Table 1). Low contamination estimates
    (0–1.353%) and high deamination frequencies (ind1: 29.6%; ind2:
    10.6%) support the authenticity of the recovered sequences
    (Table 1).
    To assess kinship and genetic affinities we carried out
    population genetic analyses of the three individuals together
    with previously published Eurasian Upper Palaeolithic and Mesolithic individuals. First, we analysed ind1 and ind2 using
    f3- and f4-statistics. The individuals have genetic affinities similar
    to those described by Fu et al. for ind3 (ref. 24). All three KremsWachtberg individuals share most alleles with each other, and
    then with individuals from the Gravettian population cluster
    named after the site of Dolní Věstonice (Czech Republic,
    ~100 km northeast)24 (Fig. 3a/b and Supplementary Data 2).
    The Burial 1 boys share significantly more alleles with ind3 than
    they do with any other Upper Palaeolithic/Mesolithic specimens
    analysed, except for Věstonice13 for whom the signal is nonsignificant (Z = −1.477, Fig. 3a and Supplementary Data 2),
    which points at close genetic ties between individuals from the
    two contemporaneous sites.

    Okay, so they didn't look at Neanderthal ancestry specifically (but you or any other interested are welcome to use their material). However, they did find a relation to the earlier individual 3 sequence, and that paper goes into Neanderthal ancestry https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4943878/ ].

    From its abstract:

    Modern humans arrived in Europe ~45,000 years ago, but little is known about their genetic composition before the start of farming ~8,500 years ago. We analyze genome-wide data from 51 Eurasians from ~45,000-7,000 years ago. Over this time, the proportion of Neanderthal DNA decreased from 3–6% to around 2%, consistent with natural selection against Neanderthal variants in modern humans. Whereas the earliest modern humans in Europe did not contribute substantially to present-day Europeans, all individuals between ~37,000 and ~14,000 years ago descended from a single founder population which forms part of the ancestry of present-day Europeans.

    The KremsWA3 individual in their paper was about 30,970 year old, had 203,986 useful SNPs, and an estimated 3.9% Neanderthal ancestry (95 % confidence interval 2.6% – 5.2%) - it belonged to the "Vestonice" genetic cluster .

    Next time someone does a larger population study along these lines, they can include the twins (and any other pertinent ancient genome material) and increase the precision and detail of such investigations.
  • Snorrie
    Excellent details regarding the DNA identification/analysis ...... Thanks. My speculative suspicion is that H. Sapiens brought measles and mumps into the H. Neanderthalis environment inducing recurrent pandemics, and critical skills population reductions which led eventually to the extinction of H. Neanderthalis. Both sub-species would have been affected. One marker of disease might/could be the loss of tooth enamel in H. Sapiens infants/children of that time period.
  • TorbjornLarsson
    Snorrie said:

    Excellent details regarding the DNA identification/analysis ...... Thanks. My speculative suspicion is that H. Sapiens brought measles and mumps into the H. Neanderthalis environment inducing recurrent pandemics, and critical skills population reductions which led eventually to the extinction of H. Neanderthalis. Both sub-species would have been affected. One marker of disease might/could be the loss of tooth enamel in H. Sapiens infants/children of that time period.

    The extinction of human populations is an interesting question where expert opinion differ.

    On Neanderthals the population genetic numbers fit that they mixed more or less completely with migrating Africans so as the simplest hypothesis that is my preference. A recent paper put in a larger context however, and it could be that it was among 3 archaic humans that were more likely to go extinct from climate change https://www.sciencedaily.com/releases/2020/10/201015111729.htm ].

    To shed light on past extinctions of Homo species including H. habilis, H. ergaster, H. erectus, H. heidelbergensis, H. neanderthalensis, and H. sapiens, the researchers relied on a high-resolution past climate emulator, which provides temperature, rainfall, and other data over the last 5 million years. They also looked to an extensive fossil database spanning more than 2,750 archaeological records to model the evolution of Homo species' climatic niche over time. The goal was to understand the climate preferences of those early humans and how they reacted to changes in climate.

    Their studies offer robust evidence that three Homo species -- H. erectus, H. heidelbergensis, and H. neanderthalensis -- lost a significant portion of their climatic niche just before going extinct.

    No doubt diseases (as well as food stress, re climate) have shaped human populations. Both Neanderthal and Denisovan alleles are adaptively selected for in modern humans https://www.sciencemag.org/news/2020/01/africans-carry-surprising-amount-neanderthal-dna , https://www.biorxiv.org/content/10.1101/2020.07.09.196444v1.full ]. There is also potentially a smidgen of Erectus that followed the other archaic genomes in at a proportionate frequency (e.g. today at ~ 0.1 % versus the few percent each of Neanderthal and Denisovan) but I think no one knows yet if it is selected for.

    But it is as hard for me to tell if there was a pandemic https://en.wikipedia.org/wiki/Pandemic ] in different populations at the time as it is tell on the species/sub-species issue.

    A pandemic (from Greek πᾶν, pan, "all" and δῆμος, demos, "people") is an epidemic of an infectious disease that has spread across a large region, for instance multiple continents or worldwide, affecting a substantial number of people. A widespread endemic disease with a stable number of infected people is not a pandemic. Widespread endemic diseases with a stable number of infected people such as recurrences of seasonal influenza are generally excluded as they occur simultaneously in large regions of the globe rather than being spread worldwide.

    I'm not even sure if they had much of widespread epidemics at the time, since populations were so scattered.

    Of your suggestions, measles is likely too young https://science.sciencemag.org/content/368/6497/1367 ].

    We sequenced the genome of a 1912 measles virus and used selection-aware molecular clock modeling to determine the divergence date of measles virus and rinderpest virus. This divergence date represents the earliest possible date for the establishment of measles in human populations. Our analyses show that the measles virus potentially arose as early as the sixth century BCE, possibly coinciding with the rise of large cities.

    In general the paramyxoviruses that measles and mumps belong to have a large range of hosts and a diverse evolutionary history https://www.nature.com/articles/s41598-017-02206-0 ]. I can't tell one way or the other about mumps before anyone has tried to locate its split date from related viruses.
  • Snorrie
    Thank you. This data gives some clarification to nettlesome questions that for me relate to the present.