Paleo diet didn't change – the climate did

Mar 18, 2014 by Janna Eberhardt
Paleo diet didn’t change – the climate did
Graph showing the isotopic shift of herbivores, wolves and humans at the transition between Neanderthals and anatomically modern humans. Credit: Hervé Bocherens/University of Tübingen

Why were Neanderthals replaced by anatomically modern humans around 40,000 years ago? One popular hypothesis states that a broader dietary spectrum of modern humans gave them a competitive advantage on Neanderthals. Geochemical analyses of fossil bones seemed to confirm this dietary difference. Indeed, higher amounts of nitrogen heavy isotopes were found in the bones of modern humans compared to those of Neanderthals, suggesting at first that modern humans included fish in their diet while Neanderthals were focused on the meat of terrestrial large game, such as mammoth and bison.

However, these studies did not look at possible isotopic variation of isotopes in the food resource themselves. In fact, environmental factors such as aridity can increase the heavy nitrogen isotope amount in plants, leading to higher nitrogen isotopic values in herbivores and their predators even without a change of subsistence strategy. A recent study published in Journal of Human Evolution by researchers from the University of Tübingen (Germany) and the Musée national de Préhistoire in Les Eyzies-de-Tayac (France) revealed that the nitrogen isotopic content of animal bones, both herbivores, such as reindeer, red deer, horse and bison, and carnivores such as wolves, changed dramatically at the time of first occurrence of modern humans in southwestern France. The changes are very similar to those seen in human fossils during the same period, showing that there was not necessarily a change in diet between Neanderthals and modern humans, but rather a change in environment that was responsible for a different isotopic signature of the same .

Fragment of jaw of a wolf from Le Moustier that was analyzed during the investigation. Credit: Hervé Bocherens/University of Tübingen

Moreover, this isotopic event coinciding in timing with the replacement of Neanderthals by modern humans may indicate that environmental changes, such as an increase of aridity, could have helped modern humans to overcome the Neanderthals. These new results, together with recently published research showing that Neanderthals had more skills and exploited more diverse food resources than previously thought, makes the biological differences between these two types of always smaller. In this context, the exact circumstances of the extinction of Neanderthals by remain unclear and they are probably more complex than just a behavioral superiority of one type of humans compared to the other.

Explore further: Neanderthals may have faced extinction long before modern humans emerged

More information: Hervé Bocherens, Dorothée G. Drucker, Stéphane Madelaine: "Evidence for a 15N positive excursion in terrestrial foodwebs at the Middle to Upper Palaeolithic transition in south-western France: Implications for early modern human palaeodiet and Palaeoenvironment." Journal of Human Evolution, dx.doi.org/10.1016/j.jhevol.2013.12.015

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JVK
1 / 5 (6) Mar 18, 2014
The companion papers [1-2] told a new short story of ecological adaptations. In the context of climate change and changes in diet... what probably was a nutrient-dependent base pair change and a variant epiallele... arose in a human population in what is now central China. ...the effect of the epiallele was adaptive and it was manifested in the context of an effect on sweat, skin, hair, and teeth. In another mammal, such as the mouse, the effect on sweat, skin, hair, and teeth is probably due to a nutrient-dependent epigenetic effect on hormones responsible for the tweaking of immense gene networks that metabolize nutrients to pheromones. The pheromones appear to control the nutrient-dependent epigenetically-effected hormone-dependent organization and hormone-activation of reproductive sexual behavior in mammals such as mice and humans, but also in invertebrates and in microbes.

adapted from: http://www.socioa...53/27989
Whydening Gyre
5 / 5 (4) Mar 18, 2014
interesting... didn't know mice "sweat"....
RealScience
5 / 5 (5) Mar 22, 2014
what probably was a nutrient-dependent base pair change

The base-pair change is to the EDAR gene.

First, do you have ANY evidence that this base pair change is nutrient-dependent?

Second, base pair changes are a well known sub-class of mutations.
Kamberov established that this mutation itself had a biological effect, rather than relying on an epialelle (http://www.ncbi.n...75602/):
We generated a knock-in mouse model and find that, as in humans, hair thickness is increased in EDAR370A mice. We identify novel biological targets affected by the mutation, including mammary and eccrine glands. Building on these results, we find that EDAR370A is associated with an increased number of active eccrine glands in the Han Chinese.


So your own previous citation, Kamberov, supports that this MUTATION contributes to adaptive evolution.
robrah
3 / 5 (1) Mar 29, 2014
Has anyone considered the possibility that Neanderthals were used as slaves and/or servants by modern humans? It seems like this relationship almost always occurs when more and less sophisticated people intermingle, especially at first.

If food became scarce due to climate change, then the less sophisticated might have been discarded, thus accounting for their disappearance.

Just an idea.
JVK
1 / 5 (4) Apr 22, 2014
do you have ANY evidence that this base pair change is nutrient-dependent?


Nutrient-dependent base pair changes linked from DNA methylation to alternative splicings of pre-mRNA and amino acid substitutions are the common thread in my model of ecological adaptations sans mutations -- as in

Reconstructing the DNA Methylation Maps of the Neandertal and the Denisovan
http://www.scienc...abstract

I cited approximately 100 articles in my published work; a 5.5 minute video representation is here: http://youtu.be/DbH_Rj9U524 Nutrient-dependent / Pheromone-controlled adaptive evolution: (a mammalian model of thermodynamics and organism-level thermoregulation)
Maggnus
5 / 5 (3) Apr 22, 2014
Hey JVK, you have stated multiple times that you won't post your pretend "revelations" here. So why do I keep seeing your debunked pseudo-scientific gish-gallop all the time? Book sales not going well?
JVK
1 / 5 (3) Apr 23, 2014
In my model, the experience-dependent de novo Creation of olfactory receptor genes links olfaction and pheromones to:

Continuous Postnatal Neurogenesis Contributes to Formation of the Olfactory Bulb Neural Circuits and Flexible Olfactory Associative Learning

http://www.jneuro...abstract

"...the OB-mutant (Fig. 7) and the late-postnatal neurogenesis mutant (Fig. 8), showed severe impairments in flexible olfactory associative learning. These results indicate that continuous postnatal neurogenesis and ongoing supply of newborn interneurons regulate optimized behaviors in flexible olfactory associative learning."