genes – Success Across Cultures

From Mandarin to Italian, How Language Shapes Genetics

11. February 2022by J. WittwerLeave a comment

Can you differentiate Mandarin from French or Italian?

Of course, you can.

The sounds of each of these languages are very different, from hard or soft consonants to long or short vowels.

Due to the dynamic sounds of each mother tongue, you can see the adaptation of different vocal tracts across cultures.

These adaptations have developed across generations according to the languages spoken in countries around the world.

We discussed gene-culture coevolution last week in relation to the human species and speech.

Now, let’s talk about how speech and language have evolved our genetics across cultures.

Physiological Traits Adapt to Language

Speech-related physiological adaptations vary across the human species according to the language spoken.

Some languages, like German or Arabic, require deep guttural sounds due to the harsh consonants.

Others, like Spanish, require speakers to roll their r’s.

One of the ways in which this presents in our physiology was reported by Discover Magazine.

Researchers found that the roof of the mouth differs across cultures, according to how vowel sounds are pronounced.

Furthermore, these anatomical variations evolve upon each generation, creating an evolution in the language itself and the sounds of speech.

The study’s author, Linguistics Expert Dan Dediu, says,

“Even small variations in the shape of our vocal tract may affect the way we speak, and this may even be amplified — across generations — to the level of differences between dialects and languages.”

The Study

How did researchers discern this change?

The study looked at over 100 people from several ethnolinguistic groups in Europe, North America, China, and across India.

MRI scans were taken of the hard palate of each participant.

Using the scans and machine learning, computer models formed a picture into the future of the hard palate and the sounds it might produce.

Five commonly used vowel sounds – the “uh” in sofa,” the “ah” in “hot,” the “oo” in “boot,” the “a” in “bat,” and the long “e” in “feet” – were plugged into the computer model.

A second generation, mimicking the sounds from the first, showed the amplified pronunciation of each sound – as did 50 generational models after it.

Though the change in the shape of the hard palate over time only impacted pronunciation slightly each generation, the change in the vowel sounds after 50 generations was much more pronounced.

The researchers write that,

“besides culture and environment, quantitative biological variation can be amplified, also influencing language.”

This research begs the question: what will our languages sound like in 50 generations…and how did they sound 50 generations ago?

Your Ancestors Couldn’t Drink Milk, But You Can: Here’s Why

28. January 2022by J. WittwerLeave a comment

Got milk?

Your ancestors didn’t.

About 10 millennia ago, human adults couldn’t drink milk.

The BBC article, “How Human Culture Influences Our Genetics,” outlines why the human adults of today are more lactose tolerant, while those of yesteryear were not.

Lactose tolerance – or intolerance – is genetic.

Prior to dairy farming, only children could manage to chug a glass of milk without getting sick.

When some cultures began dairy farming, a genetic mutation created an ability amongst adults to digest milk properly.

This mutation was passed on to offspring over time.

Last week, we discussed how culture is outpacing genetics when it comes to human evolution.

This is one example where culture may not have outpaced genetics but still worked symbiotically to evolve a tolerance to milk through natural selection.

Lactose Tolerance Today

As mentioned, those cultures with a background in dairy farming are significantly more lactose tolerant today, because they’ve developed the related gene.

This is another example of how culture impacts biological evolution.

That gene effectively produces the enzyme, lactase, which breaks down lactose (the sugar found in dairy products) in the small intestine.

Cultures with a higher prevalence of lactose intolerance see lesser production of lactase in infancy.

Upwards of 70 percent of adults from East Asian and West African cultures suffer lactose intolerance, along with those of Greek, Italian, Jewish, and Arab heritage.

On the opposite end of the spectrum, those cultures with high lactose tolerance include Northern European cultures, particularly those of the Nordic region.

The populations of Sweden and Finland have a reported tolerance of 74 percent and 82 percent, respectively.

These tolerance levels might be related to the immigration of lactose tolerant groups to these regions, rather than a background in dairy farming, as the cultures aren’t historically rooted in the production or consumption of milk.

But these countries may be the exception that proves the rule.

As anthropologist and co-author of The 10,000-Year Explosion: How Civilization Accelerated Human Evolution, Henry Harpending, writes:

“Which came first, the cattle or the mutation, you can’t tell. If the mutation had not occurred, there wouldn’t be so much dairying. But if people who could digest lactose didn’t have cattle, the mutation would have had no advantage.”

The Cow or the Milk

Although we may not know what came first – the cow or the milk tolerance – we can spot some aspects of “survival of the fittest” in the evolution of these cultures.

Cultures with higher lactose tolerance were historically able to survive famine at a higher rate and may have even made for stronger warriors, due to bone health.

In his research on the subject, Professor Daniel Wegmann of the University of Fribourg in Switzerland, concludes:

“Over the past 3,000 years, lactase-persistent individuals had more children or, alternatively, those children had better chances of survival than those without this trait.”

We can only expect lactose tolerance to grow even more within the next 3,000 years.

Does Culture Drive Human Behavior More Than Genetics?

21. January 2022by J. WittwerLeave a comment

Biologists say that behavior is ultimately determined by natural selection.

This is because genetic structures are constructed according to the mental processes and learned patterns and responses to different environments.

As Richerson and Boyd, authors of Not By Genes Alone: How Culture Transformed Human Evolution, note: physiological changes that shape behavior are evolutionary.

Take bird migration, for instance.

Instead of passing winter in harsh environments, birds have acquired their migratory behavior according to evolutionary physiological reactions.

The brain has formed evolutionary strategies across time to send hormonal signals that trigger annual migration to warmer climates.

So, while genes may determine the traits and behaviors best suited to the environment, the environment has helped shape these genes.

Where does culture come into play?

Culture is part of the environment, especially where humans are concerned.

Culture Drives Human Evolution

Taking the environment’s impact on evolution a step further, in a study by the University of Maine, culture was found to drive human evolution even more so than genetics.

According to the 2021 study by researchers, Tim Waring and Zach Wood, humans adapt to their environment and challenges in their environment via culture – in the form of learned knowledge, skills, and practices –more effectively and at a faster pace than through genetics.

One reason for this “special evolutionary transition” is that the cultural transfer of knowledge is flexible and fast when compared to genetic transfer.

Waring notes that:

“Gene transfer is rigid and limited to the genetic information of two parents, while cultural transmission is based on flexible human learning and effectively unlimited with the ability to make use of information from peers and experts far beyond parents.”

This results in a stronger adaptation via cultural evolution than genetic evolution allows.

The researchers also argue that culture’s group-oriented nature produces more group-oriented evolution as well.

Ways in Which Humans Have Evolved

How have humans evolved via culture?

Humans have adapted in several key ways over the millennia.

These include:

Capacity for social learning
Predisposition to be cooperative
Capacity to collaborate
Diminishing aggression

Genetics and culture work together to adapt behaviors, but as Waring and Wood’s research suggests, culture is becoming even more influential on the evolution of human behavior.

As Waring concludes:

“This research explains why humans are such a unique species…We are slowly becoming ever more cultural and ever less genetic.”

Nature Vs. Nurture & Cultural Evolution

14. January 202214. January 2022by J. WittwerLeave a comment

Language is culture. Food is culture. Customs are culture.

They are all taught. They are all shaped and communicated across generations through group orientation and primary socialization.

In the book, Not By Genes Alone: How Culture Transformed Human Evolution, authors Peter J. Richerson and Robert Boyd explain that some scientists argue that culture and human behavior cannot be tied to evolutionary theory and biology, quoting the concept of nature versus nurture.

Culture is something created via nurture, while biology is formed by nature.

An individual’s concept of time, her values and customs, her language – all of this is formed by the environment in which she grows up.

It is nurtured.

An individual’s eye color, his height, any genetic disease he may have – all of this is formed by genes.

It is the result of nature.

Considering this, many argue that evolutionary theory does not come into play in regards to learned behaviors that are shaped by the environment.

As we’ve discussed in many blog posts, cultural behaviors – and most other human behavior – is learned; therefore, the argument is that biology has little to do with creating it.

But Richerson and Boyd suggest that this is not the case, due to the symbiotic nature of genes and their environment.

Genes & the Environment Interact

Genes are not blueprints specifying an organism’s final draft.

Instead, the genetic information stored in an organism interacts with the environment around it while the organism is developing.

As Richerson and Boyd describe it:

“Genes are like a recipe, but one in which the ingredients, cooking temperature, and so on are set by the environment.”

And like any recipe, the traits of the organism will vary based on the differences in the environment.

Some traits are more affected by environment than others.

For instance, most humans develop two ears, despite the environment they’ve grown in, but depending on their nutritional environment during youth, they can develop different growth and health outcomes into adulthood.

Environmental differences can also cause differing behaviors in organisms that are genetically the same.

In such circumstances, the environment is the direct cause of different traits and behaviors.

And because culture is both a part of the environment and a reaction to it, while genes are the evolutionary response to past environments, neither can be removed from the equation.

They are symbiotic.

We’ll take a closer look at the degree to which genes and culture influence human behavior next week.