2022 was a big year for human evolution research—made even bigger by the awarding of the Nobel Prize in Physiology and Medicine to Svante Pääbo for his work sequencing the Neandertal genome—and with a new year, it’s worth looking back at what we learned in 2022 and what we can expect to learn more about in 2023. Themes for last year include research that focuses on using ancient DNA to give us new clues about past behaviors or genetics, learning more about behaviors of hominins, and learning how humans migrated across the globe.
1. Neandertals had a big year, and arguably one of the biggest new discoveries of 2022 related to how they lived. Ancient DNA from a teenage girl’s tooth provided evidence for Neandertal social structure. From this tooth, scientists from the Max Planck Institute of Evolutionary Anthropology discovered that a father-daughter pair and a young boy and female relative (perhaps an aunt or grandmother) were living together with 13 other individuals. This suggested that the group was living (and possibly dying) together around the same time. While learning about this particular group is exciting, what’s more exciting is the potential for the future—we now have tools and methods in place to begin understanding the social structures of our ancient relatives. As such, we can use this study to begin answering questions like whether males or females migrated from their natal groups (findings from this study suggest that females migrated) and if other Neandertal groups followed similar social structures.
2. In early December 2022, Lee Berger and colleagues announced that, for the first time, there was evidence of fire use in a cave thought to be occupied by Homo naledi. This hominin species lived in a cave system in South Africa between 335,000 and 236,000 years ago. When this new species was announced in 2015, the find was remarkable for many reasons, one of which is the number of fossils that were discovered (over 1550!). As research in the cave—known as the Rising Star cave system—continued, more behaviors were illuminated, including the use of fire. Small fireplaces containing burned animal bones combined with sooty walls throughout the cave system suggested that fires were being lit inside of the caves. More work is needed to identify how old these fireplaces may be and exactly how the fires were being used, though to date, all signs point to a pretty incredible discovery.
3. With the pandemic caused by COVID-19 still in the front of everyone’s mind, how humans became immune to certain diseases is of particular interest. New research from the University of Melbourne suggested that when modern humans mated with ancient hominins, some genes related to immunity were passed. In particular, the research team found that when humans migrated to Papua New Guinea and subsequently mated with an ancient group known as the Denisovans, Papuans inherited about 5% of the Denisovan genome. The inherited genome included about 82,000 single nucleotide polymorphisms, many of which were located by genes known to impact the human response to pathogens. Newly migrated Papuans would have been exposed to a host of new, unfamiliar tropical diseases and had little-to-no immunity to fight them. With the inheritance of Denisovan DNA, Papuans were able to develop immunity and therefore survive in this new environment much faster than they would have been able to without the admixture. More research will focus on how other humans may have inherited immune responses in other areas of the world.
4. When was the first barbeque? Perhaps 600,000+ years ago, according to a study led by Irit Zohar from the Steinhardt Museum of Natural History in Israel. Human evolution researchers have known that early humans cooked their food and evidence pointed to this behavior beginning about 170,000 years ago. But, evidence discovered from the Gesher Benot Ya’aqov site in Israel suggested hearth-related activities and also preserved freshwater fish remains. In the assemblage, a high percentage of pharyngeal teeth were discovered, compared with a low percentage of fish bones—when fish bones are exposed to high temperatures, they tend to disintegrate while the teeth remain. As such, researchers concluded that the fish may have been cooked. Moreover, the enamel on the teeth were exposed to heat between 400 and 930F, which is well within the range for cooked fish. All evidence from this site suggested that those living there discovered the benefits of cooked food—like better taste and using less energy to breakdown food—perhaps much earlier than originally thought.
5. Globalization has been a hot topic for decades, but when and how did humans first migrate around the world? A study using DNA from a team based at Florida Atlantic University found that humans migrated from the north into South America. DNA was analyzed for two individuals who lived about 1,000 years ago in northeast Brazil and then compared with the genomes of modern-day Brazilians, Panamanians, and Uruguayans. The evidence suggests that human migrations occurred along the Atlantic coast, eventually leading to modern-day Uruguay and Panama in a 3,270-mile journey. This elucidates how settlements may have occurred, suggesting that the Atlantic coast was settled after the Pacific coast and the Andes mountains. Analysis revealed Neandertal and Denisovan DNA providing support for interbreeding between the populations while also suggesting that the population who migrated to the Americas must have done so 40,000 years ago.
2022 was a big year for human evolution, and while the top discoveries are listed above, there are also some honorable mentions worth exploring: How did the Neandertals go extinct?, Neandertals might have been carnivores, a jawbone from Spain, a new theory on the evolution of bipedalism, and how humans and Neandertals may have interacted.
Sources: Nobel Prize, PLOS SciComm, John Hawks