Modern Human Ancestry Won’t Be Traced to a Single Point
While we may be attracted by the headlines of “Oldest Human Fossil Discovered” and “New Human Ancestor Found”, the idea that we’re on the route to unearthing an actual, single point in time and space for modern human origins is unlikely. A new study suggests that instead of continuing the search for where and when modern human ancestry originated, the focus should shift to solving other mysteries.
While the topic of human ancestry is undoubtedly fascinating, EurekAlert! notes that “the meanings of words like ancestor and ancestry are rarely discussed in detail.” That’s where the new study comes in, with a different perspective. A team of experts from the Natural History Museum, The Francis Crick Institute, and the Max Planck Institute for the Science of Human History Jena have presented a new paper titled ‘Origins of modern human ancestry’ in the journal Nature.
A Single Starting Point Won’t Be Found in the Genetic or Fossil Records
The study explores the current understanding about modern human ancestry and how it can be traced back to the distant past, as well as some of the human ancestors found on that timeline. It also asserts that no specific starting point can currently be identified when we’re talking about modern human ancestry.
Locations of early individuals with modern human ancestry in Eurasia, together with sites that may indicate an earlier dispersal in Asia and Sahul (the continental shelf centred on Australia). (Bergström et al. 2021/Nature)
They write: “no specific point in time can currently be identified at which modern human ancestry was confined to a limited birthplace, and that patterns of the first appearance of anatomical or behavioural traits that are used to define Homo sapiens are consistent with a range of evolutionary histories.”
Professor Chris Stringer, a co-author in the new study and researcher at the Natural History Museum explained that there just isn’t enough information to work with. He said:
Some of our ancestors will have lived in groups or populations that can be identified in the fossil record, whereas very little will be known about others. Over the next decade, growing recognition of our complex origins should expand the geographic focus of paleoanthropological fieldwork to regions previously considered peripheral to our evolution, such as Central and West Africa, the Indian subcontinent and Southeast Asia.
This cranium from Jebel Irhoud in Morocco is often called a modern human ancestor. The topic of human ancestry is carefully examined in a new study. (Chris Stringer)
Study co-author Pontus Skoglund from The Francis Crick Institute continued the idea, stating:
Contrary to what many believe, neither the genetic or fossil record have so far revealed a defined time and place for the origin of our species. Such a point in time, when the majority of our ancestry was found in a small geographic region and the traits we associate with our species appeared, may not have existed. For now, it would be useful to move away from the idea of a single time and place of origin.
- The Origin of ‘Us’: What We Know So Far About Where We Humans Come From
- ‘Distinct’ Facial Features Have Been Around For A Very Long Time
- Age of the Wise Men: What Distinguishes Homo Sapiens from the Other Great Apes?
What Should Researchers Look For Instead?
The study identifies three significant phases in human ancestry and major questions which still surround those phases. They suggest that future research should explore these avenues instead of trying to find the elusive starting point of the human story.
The first of the three points of interest is given in the paper as “the worldwide expansion of modern humans between 40 and 60 thousand years ago (ka) and their last known contacts with archaic groups such as Neanderthals and Denisovans.” A second focus “is associated with a broadly construed African origin of modern human diversity between 60 and 300 ka.” Finally, the experts believe there should be more interest in “the complex separation of modern human ancestors from archaic human groups from 0.3 to 1 million years ago.”
a, Locations of key H. sapiens, Neanderthal, Denisovan and other archaic human fossils from the past 500 thousand years. Pale colors indicate uncertain but possible lineage assignments. b, Chronology of archaic human populations that are unlikely to have contributed to modern human ancestry. These include Homo naledi, Homo floresiensis, and Homo luzonensis. (Bergström et al. 2021/Nature)
According to the study co-author Eleanor Scerri from the Pan-African Evolution Research Group at the Max Planck Institute for the Science of Human History, these major questions “concern which mechanisms drove and sustained this human patchwork, with all its diverse ancestral threads, over time and space.” Furthermore Scerri clarified that “Understanding the relationship between fractured habitats and shifting human niches will undoubtedly play a key role in unravelling these questions, clarifying which demographic patterns provide a best fit with the genetic and palaeoanthropological record.”
What’s Needed to Shift the Focus of Human Ancestry Research?
To achieve the monumental task of answering these questions, the researchers note that the ancient genetic record needs to be amplified. To do so, they suggest that improvements are necessary for the technology that is used in retrieving and screening ancient DNA, including the ability to find sedimentary ancient genetic material. More interdisciplinary work on the fossil, archaeological, and genetic records is also encouraged.
Top Image: A new study suggests three key phases in human ancestry for scientists to focus future research. Source: adrenalinapura /Adobe Stock