We think of our chewing gum as a disposable, modern habit. But what if a prehistoric version of it—a gooey, black tar made from birch bark—was a kind of “genetic time capsule”? For years, archaeologists have known that Neolithic people used this tar as both a snack and a superglue. Now, in a stunning scientific breakthrough, researchers have learned to extract ancient human DNA not just from the chewed wads, but from the very tools and pots they were used to repair. This case study explores how the microscopic secrets in ancient spit are beginning to tell us a story that has long been invisible in the archaeological record: who was doing what in the households of our 6,000-year-old ancestors.
The Information Box
Syllabus Connection:
- Paper 1: Chapter 1.3/1.8 (Archaeological Anthropology, Research Methods), Chapter 1.8 (Prehistoric Cultures: Neolithic), Chapter 9.6 (Feminist Anthropology: Gender Roles)
Key Concepts/Tags:
- Birch Bark Tar, Ancient DNA (aDNA), Bio-archaeology, Gender Division of Labor, Neolithic, Oral Microbiome
The Setting: Who, What, Where?
This case study is based on groundbreaking research by a team including Hannes Schroeder and Anna White at the University of Copenhagen, published in the Proceedings of the Royal Society B. The material at the heart of the study is birch bark tar, the world’s oldest known synthetic material. The samples were recovered from nine Neolithic archaeological sites in and around the Alps. Many of these were from ancient lake-dwelling settlements, where the waterlogged conditions were perfect for preserving organic materials like tar, even while human bones and teeth rarely survived.
The Core Argument: Why This Study Matters
This is a major methodological breakthrough that creates a powerful new source of data for understanding prehistoric life.
- A New Source of Ancient DNA: The central achievement is the ability to successfully extract ancient human DNA from a common artifact, not just from rare human remains. The tar acts as a remarkable preservative, trapping the DNA of the person who chewed it or handled it. This opens up a new frontier for genetic research, especially in environments where skeletal preservation is poor.
- A Tantalizing Glimpse into the Division of Labor: This is the most provocative finding. In their small sample, the researchers found a striking pattern:
- All four tar samples used to glue stone tools to handles contained male DNA.
- All three tar samples used to repair pottery contained female DNA. This provides the first direct, though preliminary, biological evidence suggesting a gendered division of labor in these Neolithic communities, where men were primarily associated with tool-making and women with pottery maintenance.
- Reconstructing a Prehistoric World: The DNA extracted from the tar went beyond just the humans. It provided a rich snapshot of their environment and diet. Researchers found DNA from wheat and barley (farmed crops), hazel (foraged food), sheep (domesticated animals whose products were stored in pots), and wild boar (hunted prey). This turns a simple lump of tar into a detailed ecological and dietary record.
- A New Window into Ancient Health: The chewed wads also preserved the microbes from ancient saliva, offering a new way to study the oral microbiome of Neolithic people. This is significant because it provides a different, and potentially more complete, picture of oral health and disease than the dental calculus (hardened plaque) that has traditionally been studied.
The Anthropologist’s Gaze: A Critical Perspective
- The “Who Touched It Last?” Problem: A critical anthropological question is: what does the presence of someone’s DNA on an object actually mean? As the researchers themselves caution, we cannot definitively conclude that the person whose DNA is on the tar made the object. They could have been the one who repaired it, or simply the one who chewed the tar before handing it to someone else to use as glue. The link between the DNA and the specific action is a strong inference, but not an absolute certainty.
- The Power of Bio-archaeology: This study is a perfect example of the “bio-archaeological revolution.” It shows the discipline’s shift from simply analyzing the form and style of an artifact to being able to analyze the invisible, molecular traces left on it. This allows archaeologists to move from studying “cultures” to studying the specific individuals and biological realities of the past.
- Testing the Stereotypes of Gender Roles: This new method provides a powerful scientific tool to test, rather than just assume, prehistoric gender roles. For decades, the association of men with “tools/hunting” and women with “pots/domesticity” has been a common but often unproven stereotype. This method offers the potential to replace these assumptions with direct, biological evidence, which could either confirm or radically challenge our old models.
The Exam Angle: How to Use This in Your Mains Answer
- Types of Questions Where It can be Used:
- “How are new scientific methods in archaeology changing our understanding of prehistoric societies?”
- “Critically analyze the archaeological evidence for the division of labor in prehistoric cultures.”
- “Discuss the scope and significance of bio-archaeology in modern anthropology.”
- Model Integration:
- On New Archaeological Methods: “New methods in bio-archaeology are providing unprecedented insights into the past. For example, a recent study has successfully extracted ancient human DNA from birch bark tar, using this ‘ancient chewing gum’ to identify the biological sex of individuals associated with specific artifacts like tools and pottery.”
- On Gender in Prehistory: “The traditional model of a rigid gendered division of labor in prehistory is now being tested with direct evidence. A recent analysis of DNA on Neolithic artifacts, for instance, has provided preliminary biological data suggesting men were primarily involved in tool-making and women in pottery repair, opening a new line of inquiry.”
- On Bio-archaeology: “The scope of bio-archaeology has expanded beyond skeletal remains. The analysis of ancient DNA from non-skeletal sources, such as the birch bark tar used as an adhesive on a 6,000-year-old tool, allows us to connect specific biological individuals to the artifacts they used, even in the absence of their bones.”
Observer’s Take
For centuries, the artifacts of the past have been silent objects, telling us stories about cultures but rarely about the individuals within them. This remarkable study changes that. It’s like finding a 6,000-year-old fingerprint and a DNA sample at a prehistoric “crime scene.” The discovery that this ancient, all-purpose tar is also a perfect preservative for human DNA is a scientific game-changer. It transforms a simple tool into an intimate record, a direct biological link to the person who chewed it, used it, and left their story behind in their spit. It is a powerful reminder that the past is not just populated by anonymous cultures, but by real men and women, whose lives we are only just beginning to have the tools to truly understand.
Source
- Title: Ancient chewing gum could reveal how early men and women split up their chores
- Author: Celina Zhao
- Publication: Science (via ScienceAdviser newsletter)
- Original Research: Published in the Proceedings of the Royal Society B.
