Michel Tibayrenc, Francisco J. Ayala-On Human Nature. Biology
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Chapter 46 What HIV Has Taught About the Interactions Between Biology, Culture, and Other Evolving Systems S. Mallal1,2 1Vanderbilt University School of Medicine, Nashville, TN, United States; 2Murdoch University, Murdoch, Western Australia THE INTERACTION OF EVOLUTIONARY evolutionary processes that have further accelerated the SYSTEMS appearance of additional emergent properties. Biological evolution has provided solutions to improve Although our first understanding of the evolutionary pro- survival and reproductive success, and this has imbued us cess came from biology, we can define evolution more with strong instincts to nurture our families and insiders and broadly as a gradual process in which something changes defend against external threats. These instincts were selected into a different and usually more complex or better form. A for by threats that could be defended, or opportunities that key to understanding evolutionary systems is the concept of could be exploited, in our environment when we were an emergent property as a property of a collection or hunter-gatherers. As efficient as these evolutionary processes complex system not present in its component parts. As are at providing solutions to modifiable threats or exploitable such, it could not have been predicted ahead of time. A simple example is saltiness, an emergent property of salt, present in neither sodium nor chloride on their own. The field of complexity science categorizes emergent properties Evolutionary Processes into various types (Fromm, 2005) and recognizes such EEvolutionary Processes evolutionary processes work at many levels from cosmo- logical, chemical, biological, cultural/political, commercial, scientific/technical/industrial, and regulatory amongst Regulatory* others (Fig. 46.1). 300 Scientific/Industrial* These forms of evolution operate over very differing *Dependent on 10 K Commercial* emergence of language and time frames, and for this reason the emergent properties of collective older and slower forms of evolution are more likely to exert 250 K Cultural/Political* learning in man 3.5 B Biological constraints and selective pressures on more recent or Time (Years ago) rapidly changing systems than the other way around. This 12+ B Chemical hierarchy in no way implies the greater importance of one 13+ B Cosmological field over another but rather may provide guidance of the Emergent Complexity Properties likely dominant directionality of the influences. Life on earth is estimated to have begun about 3.5 billion FIGURE 46.1 The pyramid of evolutionary processes: The universe has years ago, marking the beginning of biologic evolution. become increasing complex since its formation over 13 billion years ago. A critical threshold was the emergence of language and col- Out of this complexity, new properties have emerged such as language and lective learning that has only developed in man in the collective learning in man over the last 250,000 years. This has critically underpinned cultural and other evolutionary processes that shape our world last 250,000 years. This has underpinned downstream today. On Human Nature. http://dx.doi.org/10.1016/B978-0-12-420190-3.00046-6 771 Copyright © 2017 Elsevier Inc. All rights reserved. 772 PART | III Ethics, Politics and Religious Considerations opportunities in our environment, they do so without been met, trade and globalization has increased, and infor- simultaneously providing a rationale for why the solution mation has come to flow more freely. Altruistic cultural worked. In other words, the human brain is highly adapted, mores have emerged as we have enjoyed an unprecedented individually and collectively, to empirically solve such period of safety, affluence, and relative peace. Unfortunately, problems in our environment, but we are prone to assign an we may not be free to enjoy this as the products of intense erroneous post-hoc explanation for our success. This may cultural and commercial evolution exploit more primitive cause a problem at a later time if we act on such assump- instincts of old to recreate an environment that often feels as tions. In contrast, the more painstaking, strictly logical, and threatening as that of our hunter-gatherer past. deterministic scientific process, a more recent emergent So, what can HIV teach about the interacting evolu- system in evolutionary terms, provides understanding of tionary systems that shape our world? Specifically, why did how things work to facilitate design of solutions. the HIV pandemic emerge when and where it did, and what Language, collective learning, agriculture, industrializa- can be learned from our response to HIV that might guide tion, and globalization have also emerged as solutions to our response to other global challenges. needs of our species, mitigating many of the modifiable threats of our hunter-gatherer past that shaped our instincts. Why Did the HIV Pandemic Emerge When These emergent properties have underpinned our accelerating and Where It Did? collective progress and rendered some of our more primitive instincts, such as excessive food-seeking and other addictive The chimp virus Simian Immunodeficiency Virus (SIVcpz) behaviors, aggression, paranoia, anxiety, and similar traits was first transmitted to human hunters or bush meat ven- unnecessary or maladaptive for most aspects of everyday life dors, and mutated into HIV, in Cameroon at the beginning today (Fig. 46.2). Commercial and political evolutionary of the last century. Other species of monkey in East Africa processes can very effectively find and exploit such instincts have been found to have their own distinct stains of SIV but in an evolutionary arm race for profit as exemplified by the not get sick or die. Evolving to this mutual accommodation excesses evident in many of the most successful contempo- benefitted both the virus and host and gave these monkeys rary foods, computer games, social media, sports, entertain- infectious disease missiles with the potential to annihilate a ment, literature, media, and political strategies. closely related species competing for local resources. It is We have an instinct to move to safe, resource rich set- of no surprise then that HIV, the greatest emerging infec- tings. Remarkably we live in one of the first generations in tious disease of our time, came from the monkey species which the mass voluntary movement of people has become most similar to us. We now know that chimps themselves possible. We have therefore witnessed the establishment hunted and ate these two smaller species of ape, red-capped of remarkable genetic, ethnic and culture heterogeneity in mangabeys and greater spot-nosed monkeys, in west central the developed world and a major translocation of nearly Africa, and the SIVs from those two viruses recombined to 2 billion people from rural into urban centers in emerging create the hybrid virus SIVcpz that could infect their chimp nations. In our time, the basic needs of more people have predators and later man (Bailes et al., 2003). What Can Be Predicted What Cannot Human Behavior New emergent properties – Instincts – History no longer a guide Selected by modifiable risks from past – Shape future evolution Migration to resource rich areas Food security Huddle Globalization Attend to danger -Commerce Trust empiricism -Free flow of information Needs / Addictions -Diffusion of power Conflict / Shifting Alliances – Cultural shifts Altruism – Political shifts – Motivators / Constraints – Scientific and other discoveries – Power of diversity / Core values Pathogen Behavior – Existing Resistance, Virulence Factors – Newly Emerging FIGURE 46.2 Predicting the Future: Human and Pathogen Behavior that may been predictable compared to emergent properties that could not have been predicted before they occurred. Interactions Between Biology, Culture, and Other Evolving Systems Chapter | 46 773 Driven by the changes associated with colonialism, HIV pp65 protein of rhesus cytomegalovirus (CMV) generates a is believed to have spread from the Cameroon from the 1920s T cell response that vigorously restricts viral replication dur- by road, rail, and river links to the rapidly growing population ing primary infection but has little impact on viral shedding. of Kinshasa in the Democratic Republic of the Congo (DRC) This appears to be an example of a viral protein that has and beyond (Faria et al., 2014). Demographic, cultural, and evolved to benefit a chronic persistent virus by facilitating an economic changes also drove increased sexual promiscuity acute immune response to avoid overwhelming the host in and prostitution with an associated increase in the prevalence primary infection, while providing the host long-term benefit of sexually transmitted diseases, which are known to sub- at an individual and population level (Malouli, 2014). This stantially increase the risk of transmission of HIV. Haitian symbiotic coevolution has been disrupted since industriali- professionals who went to the DRC in the 1960s probably zation as infections such as EbsteineBarr virus (EBV) are carried the virus back to Haiti in 1964 before a single acquired later in life in the developed world, and it has been migration of HIV to the United States is believed to have proposed that this is responsible for the increasing incidence occurred around 1969 (Gilbert et al., 2007). The rare cancer of allergy and autoimmune conditions such as multiple Kaposi’s Sarcoma and infection Pneumocystis jiroveci sclerosis (Shapira et al., 2010). pneumonia were first recognized in homosexual