Cultural processes are biologically based

Natural Selection Is Still With Us

“Courtiol is not certain how strong natural selection is today, particularly in the developed world. But he says that at the very least, the data show that even as recently as 200 years ago, it still played a role in shaping humans as a species. As such, he notes, biological and cultural processes should both be considered in understanding how humans are changing through time.”

My Comments:

Background: Cultural processes are biologically based.

Explanation: Nutrient chemicals calibrate intracellular signaling and stochastic gene expression that establishes diversity in ecotypes (i.e., in the organisms that do not die of starvation). The metabolism of nutrient chemicals to pheromones that standardize and control intracellular signaling and stochastic gene expression establishes diversity in ecotype-dependent social niches, which are the basis for the development of culture.

Problem: Ignoring the molecular biology common to all organisms from microbes to man makes it appear that biological and cultural processes operate somewhat independently across species — as if there were significant differences in the molecular biology of different species. Instead, the significant differences are in the availability of nutrient chemicals and in the pre-existing genetic variation that 1) contributes to the metabolism of nutrients to pheromones; that 2) control species-specific reproduction, that 3) makes it appear that cultural processes should be considered outside the context of the basic principles of biology and levels of biological organization required to link sensory stimuli from the environment directly to changes in pre-existing genetic variations.

Solution: In the past few years, the importance of sexual selection for chemosensory cues, which are called pheromones, has been demonstrated in birds and in fish to be a requirement for adaptive evolution as it is in other species that sexually reproduce, including humans. The cultural denial of human pheromones is akin to denying that food odors do not exist, because — as I said — nutrient chemicals calibrate... and pheromones standardize and control species survival via the same molecular mechanisms.

Human Pheromones: extremely technical representation of the concept

For those interested in highly technical representations of the concept of human pheromones:

Population Genomics of Early Events in the Ecological Differentiation of Bacteria

• B. Jesse Shapiro,
• Jonathan Friedman,
• Otto X. Cordero,
• Sarah P. Preheim,
• Sonia C. Timberlake,
• Gitta Szabó,
• Martin F. Polz,
• and Eric J. Alm

Science 6 April 2012: 336 (6077), 48-51. [DOI:10.1126/science.1218198]

Abstract (subscription required to read the full text of this article)

Genetic exchange is common among bacteria, but its effect on population diversity during ecological differentiation remains controversial. A fundamental question is whether advantageous mutations lead to selection of clonal genomes or, as in sexual eukaryotes, sweep through populations on their own. Here, we show that in two recently diverged populations of ocean bacteria, ecological differentiation has occurred akin to a sexual mechanism: A few genome regions have swept through subpopulations in a habitat-specific manner, accompanied by gradual separation of gene pools as evidenced by increased habitat specificity of the most recent recombinations. These findings reconcile previous, seemingly contradictory empirical observations of the genetic structure of bacterial populations and point to a more unified process of differentiation in bacteria and sexual eukaryotes than previously thought.

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My comment on the full text of this article is apparently not going to be published so I will add it here:

Isn’t it most likely that nutrient chemicals establish the ecological niche of different bacterial species and that nutrient calibrated receptor-mediated  events link the metabolism of nutrients to pheromones that standardize and  control speciation (e.g., via changes in intracellular signaling and  stochastic gene expression)? This would link microbes to man via the origins of the olfactory and immune systems with a clear evolutionary trail that can be followed by the development of olfaction and odor receptors. I’m having difficulty opening up a dialogue in this regard, despite my publication history, and current position in microbiology. Can anyone advise me on errors in logic, basic principles of biology, or levels of biological organization
in this regard?

Pre-existing genetic variability or random mutations: a matter of priorities and choices

A matter of priorities: Bacteria evolved way to safeguard crucial genetic material

“The study, published online today in Nature, shows that bacteria have evolved a mechanism
that protects important genes from random mutation, effectively reducing the risk of self-destruction.”

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My comments on what the actual article tells us in: Evidence of non-random mutation rates suggests an evolutionary risk management strategy

Non-random mutation, as evidenced by ‘hot’ and ‘cold’ genes involved in amino-acid biosynthesis, energy metabolism, and catabolism of specific compounds is compatible with a model where 1) nutrient chemicals calibrate intracellular signaling and stochastic gene expression, and 2) the metabolism of nutrients to pheromones standardizes and controls reproduction.

This is the model detailed in Human pheromones and food odors: epigenetic influences on the socioaffective nature of evolved behaviors. The honeybee is the invertebrate model organism that extends the common molecular biology across species from microbes to man, but additional support for my conceptualization can now be found in what was recently reported on threespine stickleback fish, a vertebrate model organism of speciation.

“The study also shows that stickleback evolution is accelerated by the use of pre-existing genetic variation, instead of waiting for new, random mutations to arise, Wray explains.”

Evolutionary theorists have been loudly shouting for years that “[RANDOM] Mutations are the reason each of us is unique. These changes to our genetic material are at the root of variation between individuals, and between cells within individuals.” Indeed, it seems that the theorists may continue to focus on non-random mutations instead of the more obvious scientifically established fact that pre-existing genetic variation enables adaptive evolution, and random mutation does not.

For example, the pre-existing genetic variation that allows a cell to adapt to changes in the availability of nutrients from its environment appears to have be programmed into the first living cell(s). Receptor-mediated cellular changes in metabolism of the nutrients enable cell to cell signaling that varies with the metabolism of nutrients to pheromones.

This fact can be  explained to a general audience by saying that food odors cause us to eat what causes us to produce pheromones that cause us to associate, or not associate, with other people. In this context, pheromones are social odors.

A matter of choices:

Pre-existing genetic variations across species makes food choice essential to individual survival, and it makes mate choice essential to species survival in species that sexually reproduce. An organism that eats the wrong food may not live to reproduce. Clearly, the pre-existing genetic variations make the effects of different foods on hormones that affect our behavior a key indicator of how pre-existing genetic variability can effect hormones and their metabolism to pheromones that cause changes in sexual behavior.

The allegorical representation of this newly established scientific truth occurs in Genesis with a story indicating that what Eve decided to eat epigenetically altered events across Creation (i.e.,  based on pre-existing genetic variability, not random mutations).   Nevertheless, incorporating similar important choices into thoughts and decisions about what we eat and our mate choice may be easier for those who continue to think the development of their behavior was determined by random mutations. After all, who’s going to hold them accountable for not recognizing the truth about the difference between pre-existing genetic variations and random mutations?

Adam’s rib: Pheromones and the adaptive evolution of human sexuality

Adam’s rib, revisited: Evolutionary divergence of mammalian sex chromosomes

The article linked (above) may be of interest in the context of my comments and response to commentary linked below.

“Simpler life doesn’t have chromosomes. It has DNA rings and those rings can be captured from other organisms. Either by non-hostile exchange or eating each other.”

I don’t think ingestion of heterospecific DNA by microbes is widely known, and was reluctant to suggest it as a precursor to the self / non-self recognition that accompanies the adaptive evolution of sex differences in yeasts. But, I did in: Human pheromones and food odors: epigenetic influences on the socioaffective nature of evolved behaviors.

Here’s the section head and excerpted text from:

An epigenetic continuum from microbes to humans: from theory to facts

“Among different bacterial species existing in similar environments, DNA uptake (Palchevskiy & Finkel, 2009) appears to have epigenetically ‘fed’ interspecies methylation and speciation via conjugation (Fall et al., 2007; Finkel & Kolter, 2001; Friso & Choi, 2002). This indicates that reproduction began with an active nutrient uptake mechanism in heterospecifics and that the mechanism evolved to become symbiogenesis in the conspecifics of asexual organisms (Margulis, 1998). In yeasts, epigenetic changes driven by nutrition might then have led to the creation of novel cell types, which are required at evolutionary advent of sexual reproduction (Jin et al., 2011). These epigenetic changes probably occur across the evolutionary continuum that includes both nutrition-dependent reproduction in unicellular organisms and sexual reproduction in mammals. For example, ingested plant microRNAs influence gene expression across kingdoms (Zhang et al., 2012). In mammals, this epigenetically links what mammals eat to changes in gene expression (McNulty et al., 2011) and to new genes required for the evolutionary development of the mammalian placenta (Lynch, Leclerc, May, & Wagner, 2011) and the human brain (Zhang, Landback, Vibranovski, & Long, 2011).”

My academic and commercial interest in this complex ability in bacteria that suppress reproduction with pheromones when insufficient nutrients are available led me to sponsor the video game “Bacillus.” One entitlement is that I get to name an organism and attribute to it a characteristic. If a named organism eats the DNA of other bacteria, I named it!  If you want to encourage others to have some fun while learning about the  molecular biology of sex differences,  there is still time to contribute to the game’s development and get credit for doing so.

Creation vs Evolution? Pre-existing genetic variation, not random mutation

Article link:

Stickleback genomes reveal path of evolution

“…evolution is accelerated by the use of pre-existing genetic variation, instead of waiting for new, random mutations to arise…”

Full text is free: Jones, F. C. et al. Nature. http://dx.doi.org/10.1038/nature10944 (2012).

My Comment to the Nature site:

The honeybee is an invertebrate model organism that exemplifies the vertebrate molecular mechanisms detailed here. As noted by the authors, these molecular mechanisms are common to microbial species, which indicates the requirement for their ubiquitous and consistent use across life’s evolutionary continuum.

In the honeybee, what the queen eats determines her pheromone production and everything else about the colony, including the neuroanatomy of the worker bee’s brains. From this perspective on molecular biology, the honeybee model tells us that nutrient chemicals calibrate receptor-mediated intracellular signaling and stochastic gene expression associated with the metabolism of nutrients to pheromones in all species from microbes to man. The pheromones standardize regulatory control of receptor-mediated intracellular signaling and stochastic gene expression required for speciation. Reciprocal bottom-up / top-down relationships among chemicals associated with the “odors” of food are directly responsible for the formation of an ecological niche, which is maintained by the “social odors” / the pheromones that establish the social niche.

Changes in nutrient chemicals result in changes in the ecological niche that change the social niche by partial suppression of reproduction in individuals that don’t “smell” right because they are malnourished (or in bacterial colonies where reproduction is suppressed by pheromones and quorum sensing). The ability to acquire sufficient nutrient chemicals is genetically predisposed but also depends on conspecifics and stressors in the social niche (e.g., dominance in mammals) that might prevent access to changing supplies of existing nutrients. Individuals with genetic predispositions that allow them to adapt to changes associated with available nutrients will reproduce in microbial species like bacteria, or pheromonally signal their reproductive fitness in yeasts or in the multicellular organisms of all other species. These nutritional and social stressors are associated with immune system dysfunction in primates as they are with nutritional deficits or excess in other species.

In species from yeasts to primates, this model allows incorporation of social science theories of individual selection, kin selection, and group selection where nutrition and food odors are as essential to individual survival as they are to the production of pheromones and species survival. In this context, olfaction and odor receptors provide a clear evolutionary trail that can be followed from unicellular organisms to insects to humans.