A new study conducted by an interdisciplinary team of archaeologists, geneticists, and isotope experts, and published in PLOS ONE, investigated the movement of people in this period at a single regional center, a Bronze Age city-state called Alalakh in present-day southeastern Turkey. Their results indicate that the majority buried at Alalakh were raised locally and descended from people who lived in the region.

The team’s goal was to see if the high levels of interregional connectivity evidenced by the architecture, texts, and artifacts found at the site during 20 years of excavations, sponsored by the Turkish Ministry of Culture and Tourism and Hatay Mustafa Kemal University, could be detected among the population buried at the city.

To do so, they conducted strontium and oxygen isotope analyses on tooth enamel, which can detect whether an individual grew up locally at Alalakh or moved there only during adulthood. The genetic data on the other hand can be used to determine where a person’s recent ancestors came from.

The isotope analysis identified several non-local individuals. However, their DNA showed an ancestry that was local to Alalakh and neighbouring regions. “There are two possible explanations for our findings,” said co-lead author Stefanie Eisenmann from the Max Planck Institute for the Science of Human History. “Either these individuals are short-distance migrants from the region or return-migrants, people whose parents or grandparents originally came from Alalakh.”

Only one sampled individual, an adult woman, was not part of the local gene pool, instead showing ancestry that most closely matched groups in Central Asia. However, her isotopic signatures suggested a local upbringing. “We expected the isotope analysis to show that this person immigrated to Alalakh, since her genetic data was so different from the rest of the population, so we were surprised to see that she was likely native to Alalakh. It could have been her parents or grandparents who made the move, instead,” explained Tara Ingman, the other lead-author of the study from Koç University.

While different types of mobility were identified, including short-distance, long-distance, and return migration, there were no complete foreigners in the dataset. Most people were born and raised at Alalakh and also their ancestors came from the region.

“There are several ways to explain this. It is possible that far less long-distance migrants were living at Alalakh than we had previously thought. Another possibility is that we haven’t found their graves, yet. Perhaps most individuals that came from far away were not buried directly at Alalakh, or in a way we cannot trace,” said Murat Akar, director of the excavations.

Our proclivity for socialization is lifelong, equally prominent in the lives of adolescents and adults. A recent study determined key differences in the ways that various age groups communicate, as well as one conversational component that stands the test of time: friendship. Specifically, bonds between individuals who identify as female.

Led by former Beckman Institute postdoctoral researchers Michelle Rodrigues and Si On Yoon, an interdisciplinary team evaluated how interlocutors’ age and familiarity with one another impacts a conversation, reviewing the interaction’s overall effectiveness and stress responses generated as a result.

The study, titled “What are friends for? The impact of friendship on communicative efficiency and cortisol response during collaborative problem solving among younger and older women,” was published in the Journal of Women and Aging in May 2021.

Two hypotheses form the foundation of this female-focused study. First, the tend-and-befriend hypothesis, which challenges the traditionally masculine “fight-or-flight” dichotomy.

“Women have evolved an alternative mechanism in response to stress,” said Rodrigues, who is currently an assistant professor in the Department of Social and Cultural Sciences at Marquette University. “In order to deal with stress, women can befriend female peers.”

The team also tested the socio-emotional selectivity hypothesis, which postulates a social “pruning” as humans advance in age and pursue more intimate, higher-quality circles of friends.

The introduction of age as a variable is novel in the field and stems from an interdisciplinary Beckman collaboration.

“I was working with several different groups in several different disciplines, coming from the perspective of studying friendship but having previously done research on adolescent girls, but not older women,” Rodrigues said.

She combined forces with then-Beckman-postdoc Si On Yoon, who was studying the cognitive mechanisms of natural conversation across the lifespan, including healthy younger and older adults.

“My research program was focused on language measures in social interactions, and I was glad to work with Dr. Rodrigues to develop an integrative approach including both language processing and physiological measures to study social interactions,” said Yoon, who is currently an assistant professor in the Department of Communication Sciences and Disorders at the University of Iowa.

The interdisciplinary team merged both theories into a single query: Across women’s lifespans, how are the tendencies to “tend and befriend” as well as socially select reflected in their communication?

They tested a pool of 32 women: 16 “older adults” aged 62-79, and 16 “younger adults” aged 18-25. Each participant was either paired with a friend (a “familiar” conversation partner) or a stranger (“unfamiliar”).

The partnerships underwent a series of conversational challenges, wherein the participant instructed her partner to arrange a set of tangrams in an order that only the former could see. The catch? Each shape was abstract, their appearances purposefully difficult to describe.

“You could look at one [tangram] and say, ‘This looks like a dog.’ Or, you could say, ‘This looks like a triangle, with a stop sign, and a bicycle wheel,'” Rodrigues said.

This exercise helped quantify each conversation’s efficiency: partners who achieved the desired tangram arrangement in fewer words were considered more efficient, and pairs who needed more words to complete the task were considered less efficient.

The researchers found that while the younger adult pairs communicated more efficiently with familiar partners than their older counterparts, they communicated less efficiently with unfamiliar partners; alternatively, the older adults demonstrated conversational dexterity, quickly articulating the abstract tangrams to friends and strangers alike.

“A referential communication task like this requires that you see where the other person is coming from. It seems like the younger adults are a little more hesitant in trying to do that, whereas the older adults have an easier time doing that with strangers,” Rodrigues said.

This was not predicted based on the socio-emotional selectivity hypothesis, which anticipated a correlation between age and social isolation.

“Even though older adults choose to spend more time with people who matter to them, it’s clear that they have the social skills to interact with unfamiliar people if and when they choose to,” Rodrigues said.

Rodrigues’ team also measured salivary cortisol to quantify and compare participants’ stress levels throughout the testing process.

“When you experience something stressful, if you have a stress response system that’s working as it should, the result is an elevated amount of cortisol, our primary stress hormone, which then tells our bodies to release glucose into our bloodstreams,” she said. “That’s reflected in our saliva about 15 to 20 minutes after we experience it. If we see a rise in salivary cortisol from an individual’s baseline levels, that indicates that they are more stressed than they were at the time of the earlier measurements.”

Across both age groups, those working with familiar partners had consistently lower cortisol levels than those working with unfamiliar partners.

“A lot of the research on the tend-and-befriend hypothesis has only focused on young women, so it’s great to have these results that pull that out to the end of life. We can see that friendship has that same effect throughout the lifespan. Familiar partners and friendship buffer stress, and that’s preserved with age,” Rodrigues said.

Proteins are so fundamental that DNA — the genetic material that makes each of us unique — is essentially just a long sequence of protein blueprints. That’s true for animals, plants, fungi, bacteria, archaea, and even viruses. And just as those groups of organisms evolve and change over time, so too do proteins and their component parts.

A new study from University of Illinois researchers, published in Scientific Reports, maps the evolutionary history and interrelationships of protein domains, the subunits of protein molecules, over 3.8 billion years.

“Knowing how and why domains combine in proteins during evolution could help scientists understand and engineer the activity of proteins for medicine and bioengineering applications. For example, these insights could guide disease management, such as making better vaccines from the spike protein of COVID-19 viruses,” says Gustavo Caetano-Anollés, professor in the Department of Crop Sciences, affiliate of the Carl R. Woese Institute for Genomic Biology at Illinois, and senior author on the paper.

Caetano-Anollés has studied the evolution of COVID mutations since the early stages of the pandemic, but that timeline represents a vanishingly tiny fraction of what he and doctoral student Fayez Aziz took on in their current study.

The researchers compiled sequences and structures of millions of protein sequences encoded in hundreds of genomes across all taxonomic groups, including higher organisms and microbes. They focused not on whole proteins, but instead on structural domains.

“Most proteins are made of more than one domain. These are compact structural units, or modules, that harbor specialized functions,” Caetano-Anollés says. “More importantly, they are the units of evolution.”

After sorting proteins into domains to build evolutionary trees, they set to work building a network to understand how domains have developed and been shared across proteins throughout billions of years of evolution.

“We built a time series of networks that describe how domains have accumulated and how proteins have rearranged their domains through evolution. This is the first time such a network of ‘domain organization’ has been studied as an evolutionary chronology,” Fayez Aziz says. “Our survey revealed there is a vast evolving network describing how domains combine with each other in proteins.”

Each link of the network represents a moment when a particular domain was recruited into a protein, typically to perform a new function.

“This fact alone strongly suggests domain recruitment is a powerful force in nature,” Fayez Aziz says. The chronology also revealed which domains contributed important protein functions. For example, the researchers were able to trace the origins of domains responsible for environmental sensing as well as secondary metabolites, or toxins used in bacterial and plant defenses.

The analysis showed domains started to combine early in protein evolution, but there were also periods of explosive network growth. For example, the researchers describe a “big bang” of domain combinations 1.5 billion years ago, coinciding with the rise of multicellular organisms and eukaryotes, organisms with membrane-bound nuclei that include humans.

The existence of biological big bangs is not new. Caetano-Anollés’ team previously reported the massive and early origin of metabolism, and they recently found it again when tracking the history of metabolic networks.

The historical record of a big bang describing the evolutionary patchwork of proteins provides new tools to understand protein makeup.

“This could help identify, for example, why structural variations and genomic recombinations occur often in SARS-CoV-2,” Caetano-Anollés says.

He adds that this new way of understanding proteins could help prevent pandemics by dissecting how virus diseases originate. It could also help mitigate disease by improving vaccine design when outbreaks occur.

The article, “Evolution of networks of protein domain organization,” is published in Scientific Reports. The work was supported by the National Science Foundation and the U.S. Department of Agriculture.

The Department of Crop Sciences is in the College of Agricultural, Consumer and Environmental Sciences at the University of Illinois.