A recent study has revealed a connection between ancient Neanderthal DNA and the inclination of some individuals today to wake up early. This research, tracing its roots to the historical interbreeding of Neanderthals and early modern humans in Eurasia, suggests that inherited Neanderthal genetic variations play a role in shaping the sleep patterns of their contemporary human descendants. Source: SciTechPost.com
The journal Genome Biology and Evolution, published by Oxford University Press, has released a new study indicating that genetic contributions from Neanderthal forebears might be the reason behind the tendency of some modern people to naturally prefer waking and sleeping early.
Human Evolutionary Journey and Genetic Influences
Modern humans, anatomically similar to current populations, originated in Africa around 300,000 years ago. Environmental conditions in Africa influenced their early biological traits. Around 70,000 years ago, ancestors of today’s Eurasians began migrating from Africa into Eurasia, where they encountered Neanderthals and Denisovans, who had been living there for over 400,000 years. These archaic human groups had split from the lineage leading to modern humans about 700,000 years ago, evolving separately under varying environmental pressures. This led to distinct genetic variations and physical characteristics within each group. The intermingling of modern humans with these archaic groups in Eurasia introduced the possibility of acquiring genetic traits adapted to those new environmental conditions.
Archaic DNA’s Impact on Contemporary Human Characteristics
Prior research has shown that while most genetic remnants from archaic human species were phased out through natural selection, some genetic variants survived and demonstrate signs of having been advantageous. These include variations influencing high altitude hemoglobin levels in Tibetans, immunity to novel pathogens, skin pigmentation, and fat composition.
Understanding the evolution of circadian rhythms has been a focus in studies on insects, plants, and fishes, but less so in humans. Given that Neanderthals and Denisovans lived in Eurasian regions with greater seasonal daylight variability than the African environments of early modern humans, the study investigated potential genetic differences in circadian rhythms between these groups.
Study Approach and Discoveries
The research team identified 246 circadian-related genes through literature review and expert input. They found numerous lineage-specific genetic variants capable of affecting these circadian genes. Using AI techniques, they pinpointed 28 circadian genes in archaic humans with potential splice-altering variants and 16 genes with divergent regulation compared to modern humans. This suggests functional disparities in their circadian clocks.
To confirm this, the team analyzed genetic data from a large cohort of individuals in the UK Biobank, focusing on inherited Neanderthal variants and their association with sleep and wakefulness preferences. They discovered many such variants affecting sleep tendencies, particularly increasing morningness, indicating adaptation to northern latitudes similar to other animals.
The tendency towards morningness, linked with a shorter circadian rhythm, appears beneficial for adaptation to extended daylight periods in higher latitudes. This adaptation was likely evolutionarily advantageous for ancestors living in northern Europe, suggesting a Neanderthal trait worthy of preservation.
John A. Capra, the study’s lead author, emphasizes the significant genetic differences between Neanderthal and modern human circadian systems. The Neanderthal DNA in modern humans predominantly influences genes controlling circadian rhythms towards morningness. This adaptation aligns with the impact of higher latitudes on animal circadian clocks, facilitating quicker adaptation to seasonal light changes. Future research aims to extend these analyses to diverse human populations, examine the impact of identified Neanderthal variants on circadian rhythms in model systems, and apply similar methods to other adaptive traits.
Citation: “Archaic Introgression Shaped Human Circadian Traits” by Keila Velazquez-Arcelay, Laura L Colbran, Evonne McArthur, Colin M Brand, David C Rinker, Justin K Siemann, Douglas G McMahon and John A Capra, 14 December 2023, Genome Biology and Evolution. DOI: 10.1093/gbe/evad203
Frequently Asked Questions (FAQs) about Neanderthal DNA Circadian Rhythms
How does Neanderthal DNA affect modern human sleep patterns?
Recent studies have found that genetic variants inherited from Neanderthals may influence the circadian rhythms of modern humans, particularly making some individuals more inclined to be early risers.
What was the purpose of the study published in Genome Biology and Evolution?
The study aimed to explore the impact of Neanderthal genetic contributions on the sleep and wakefulness preferences of modern humans, with a focus on the tendency to wake up early.
How were archaic human genes identified as influencing modern human traits?
Researchers used a combination of literature review and expert knowledge to identify 246 circadian genes, finding specific genetic variants from archaic humans that potentially affect these genes.
What did the research reveal about the circadian clocks of Neanderthals and modern humans?
The research indicated functional differences in the circadian clocks between archaic hominins, like Neanderthals, and modern humans. This was determined through the analysis of genetic variants that influence circadian genes.
What are the implications of increased morningness in humans due to Neanderthal DNA?
Increased morningness, associated with a shortened circadian clock, likely was advantageous for adaptation to the extended summer light periods at higher latitudes. This trait, derived from Neanderthal genetics, may have been beneficial for our ancestors in northern regions.
Future research includes examining the effects of the identified Neanderthal variants on circadian clocks in model systems, applying the analyses to more diverse human populations, and exploring other traits potentially influenced by archaic human DNA.
More about Neanderthal DNA Circadian Rhythms
- SciTechPost.com Article on Neanderthal DNA and Sleep Patterns
- Oxford University Press: Genome Biology and Evolution Journal
- UK Biobank Research on Genetic Variants and Sleep Preferences
- Study on Human Evolution and Genetic Adaptation in Africa
- Research on Archaic Hominin Genes and Modern Human Traits
- Artificial Intelligence Methods in Genetic Research
- Circadian Gene Studies in Different Species
- DOI Link to “Archaic Introgression Shaped Human Circadian Traits” Article