Distribution
of malaria in Italy, 1944 (Wikicommons). Malaria used to be common in parts of
Italy, particularly Sardinia.
Gene-culture
coevolution seems to be attracting more interest. According to Google Scholar, this term is appearing
in more and more scientific articles:
2010-2017
- 248 mentions per year
2000-2009
- 107 mentions per year
1990-1999
- 22 mentions per year
1980-1989
- 31 mentions per year
I’d like to take some of the credit, but most of it actually goes to John Hawks and the landmark paper he authored in 2007 with Eric Wang, Greg Cochran, Henry Harpending, and Robert Moyzis. That paper, more than any other, changed the way we view the relationship between genetic evolution and cultural evolution in our species.
Rinaldi
(2017) provides a good review of this field of research. He starts off with a
definition of gene-culture coevolution:
"[All] organisms adapt to their environment, and in humans much of our environment is defined by our culture. Hence, cultural change can actually spur on adaptive evolution in humans", wrote evolutionary biologist Alan Templeton at Washington University in St. Louis, MO, USA. Following this argument, culture, social learning and technology have not replaced biological adaptation. Rather, human evolution is driven by the environmental conditions we created ourselves through culture, a process that has been accelerating since the beginning of agriculture and urban civilization.
Indeed, human genetic evolution sped up more than a hundred-fold some 10,000 years ago, when hunting and gathering gave way to farming, which in turn led to population growth and larger, more complex societies. Our ancestors were no longer adapting to relatively static natural environments but rather to faster-changing cultural ones of their own making. They created new ways of life, which in turn influenced who would survive and who wouldn't (Hawks et al. 2007).
Among
other changes, farming exposed humans to new diseases. "Virulent epidemic
diseases, including smallpox, malaria, yellow fever, typhus, and cholera,
became important causes of mortality after the origin and spread of
agriculture" (Hawks et al. 2007). This causation has been amply documented
in the case of malaria:
If malaria was contracted by humans in the Pleistocene, it likely would have been in isolated incidences. For example, recent genetic analysis of the glucose-6-phosphate dehydrogenase gene, some variants of which confer resistance to the infection, confirmed that malaria is a recent selective force in human populations, occurring within the last 10,000 years. Based on the mitochondrial genome of the parasite itself, Joy et al. concluded that though the parasite that causes falciparum malaria originated long ago (perhaps 50,000-100,000 YBP), a sudden increase in the population size of the parasite did not occur until around 10,000 years ago when humans began to practice agriculture.
[...] Livingstone argued that slash-and-burn agriculture in West Africa would have exposed populations to Anopheles gambiae, the mosquito that serves as the vector for Plasmodium falciparum, the cause of malaria. Slash-and-burn agriculture resulted in sedentary populations surrounded by the pools of sunlit water required for propagation of the Anophelese mosquito. (Harper and Armelagos 2010)
Farming changed the adaptive equilibrium between the human body and Plasmodium falciparum. A new equilibrium arose in those human populations that had to coevolve with a high incidence of this parasite. Now, modern health measures are upsetting this equilibrium, and those same populations are falling prey to certain diseases—ironically, because of efforts to fight another disease:
The increase in multiple sclerosis and probably other autoimmune diseases such as type 1 diabetes in Sardinia, Italy, has been linked to the elimination of malaria from the island in the early 1950s. Centuries of exposure to Plasmodium falciparum would have shaped the human immune system to aggressively fight the parasite with a tendency to over-respond to triggering factors even after the disappearance of the parasites. Recent research has indeed identified a number of gene variants involved in malarial resistance and increased risk of multiple sclerosis in Sardinians. (Rinaldi 2017)
Human culture has created new environments of biological adaptation, and these environments differ from one human population to the next because human culture likewise differs from one to the next. Subsequent cultural change will therefore have a greater biological impact on some populations than on others. This is a general principle and is not limited to the above example of malaria.
In
my next post, I will explore the biological impacts of another cultural change:
the shift from a "thick" to a "thin" social environment. A
"thick" social environment is characterized by intense interaction
with a relatively small number of people. This interaction is not only
recurrent but also predictable because it is constrained and structured by
social rules. A "thin" social environment is characterized by
interaction with more people on a less frequent basis, and this interaction is
less predictable because social relations are less constrained and less
structured.
Human
cultures fall along a continuum from "thick" social environments,
such as exist in small bands of hunter-gatherers, to "thin" social
environments, such as exist in large societies where conditions for personal autonomy
are optimal. In the latter, people are freer not only to change their networks
of social interaction but also to reduce them to the minimum necessary for
personal survival.
For
several centuries, the West has been expanding personal autonomy by transferring
collective authority from personal “bottom-up” structures (family, clan, ethny)
to impersonal “top-down” structures (the State). Beginning in the 19th century,
we have exported this cultural model to the rest of the world. Have there been
adverse effects? And have they been worse in some human populations than in
others? Most experts would answer “Yes” to both questions, while adding that
the adverse effects are temporary. Once everyone has grown accustomed to being
merely individuals, the effects should be pretty much the same everywhere.
I
will argue that some of these adverse effects will be permanent in all human populations.
This is because no population has ever fully adapted to a social environment
where individualism is at a maximum and where the State has largely replaced traditional
“bottom-up” structures. I will also argue that these permanent adverse effects
will be worse in some populations than in others.
****************************************************
I've
been trying to measure the degree to which my blog is being
"deplatformed," i.e., intercepted by blocking software. This search
took me to the site Easy Counter,
which told me that Evo and Proud is
"poorly socialized" and may be "penalized." I also learned something
else: on March 13, 2018, my blog was set to expire in 4 months. To date, no one
has notified me of this decision, and I would still be unaware if I hadn’t gone
to Easy Counter.
As
I understand it, this sort of thing happens when a blog is inactive. Blogger is supposed to be free, and I've
never had to renew my registration through an annual payment. So I'm asking you
for advice. For whatever reason, Google
wants to terminate this blog. Should I fight this decision or migrate to
another platform? If so, which one would be best? And what is the easiest way
to transfer all of my blog posts?
References
Harper,
K. and G. Armelagos. (2010). The changing disease-scape in the third epidemiological
transition, Int J Environ Res Public
Health. 7(2): 675-697.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2872288/
Hawks,
J., E.T. Wang, G.M. Cochran, H.C. Harpending, and R.K. Moyzis. (2007). Recent
acceleration of human adaptive evolution. Proceedings
of the National Academy of Sciences (USA), 104: 20753-20758.
https://www.researchgate.net/profile/Henry_Harpending/publication/5761823_Recent_Acceleration_of_Human_Adaptive_Evolution/links/0c9605240c4bb57b55000000.pdf
Rinaldi,
A. (2017). We're on a road to nowhere. Culture
and adaptation to the environment are driving human evolution, but the
destination of this journey is unpredictable, EMBO reports 18: 2094-2100
https://www.researchgate.net/profile/Andrea_Rinaldi2/publication/321214867_We%27re_on_a_road_to_nowhere_Culture_and_adaptation_to_the_environment_are_driving_human_evolution_but_the_destination_of_this_journey_is_unpredictable/links/5a2692eaa6fdcc8e866da26e/Were-on-a-road-to-nowhere-Culture-and-adaptation-to-the-environment-are-driving-human-evolution-but-the-destination-of-this-journey-is-unpredictable.pdf
