Uncovering the Mystery: How a Catastrophe 110,000 Years Ago Led to the Demise of Neanderthals

Recent DNA research reveals a troubling trend for Neanderthals. About 110,000 years ago, their genetic diversity began to drop sharply. This decline foreshadowed their extinction around 70,000 years later. A recent study has looked at an unusual aspect of this decline: Neanderthal ears.

Led by paleontologist Alessandro Urciuoli from Universitat Autònoma de Barcelona, an international team examined Neanderthal semicircular ear canals. These small tubes in the inner ear play a key role in balance. By studying them over different time periods, researchers confirmed that Neanderthals did indeed experience a genetic bottleneck—meaning a significant loss of genetic variation due to a small population. This loss didn’t lead to extinction right away, but it set the stage for their eventual demise.

Rolf Quam, an anthropologist from Binghamton University, noted that the inner ear is formed at birth and is under strict genetic control. This makes the semicircular canals a valuable tool for studying the evolutionary history of Neanderthals. The research provides new insights into their genetic diversity.

The team compared the ear canals of Neanderthals from different eras: “pre-Neanderthal” fossils from Spain that are 400,000 years old, early Neanderthal fossils from Croatia about 130,000 years old, and “classic” Neanderthal remains from various regions. They found that classic Neanderthals had much less physical variation in their semicircular canals compared to their predecessors. This supports earlier DNA research that identified a major loss of genetic variation.

Mercedes Conde-Valverde, a co-author of the study, highlighted that their broad fossil analysis painted a clear picture of Neanderthal evolution. The difference in diversity between the early and classic Neanderthals was striking, providing strong evidence of the bottleneck.

Interestingly, the researchers made an unexpected discovery regarding early Neanderthals. They had anticipated finding a clear drop in morphological variation between the earliest Neanderthals and their ancestors. However, the pre-Neanderthals showed a level of diversity comparable to the early Neanderthals, which challenges previous assumptions about a bottleneck at the start of their lineage.

Neanderthals went extinct around 40,000 years ago, but the reasons remain unclear. It is known that they interbred with early modern humans, leading to their gradual absorption into our species. This genetic mixing highlights the impact of Neanderthals on modern humans, some of which we still carry today.

Population bottlenecks often occur due to dramatic declines in numbers caused by environmental disasters, climate shifts, or food shortages. While the research does not pinpoint the exact cause of the Neanderthal bottleneck, their reduced genetic diversity likely left them more vulnerable to these challenges.

The Neanderthal extinction didn’t happen immediately after the population crash, but the research suggests that this event played a crucial role in sealing their fate. Overall, this study deepens our understanding of Neanderthals and their demographic evolution, shedding light on how they relate to us today.

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Diversity,ears,Paleontology