Our emails are made to shine in your inbox, with something fresh every morning, afternoon, and weekend. Scientists looking to understand the evolutionary roots of human behavior have frequently looked to bonobos, the great ape native to the Democratic Republic of Congo. From a human perspective, bonobos appear a peaceful species. They live in matriarchal, highly-cooperative groups, share food and mates with outsiders, and often resolve conflicts through sex instead of aggression.
But in a recent study in the journal Current Biology , a pair of researchers from Duke University found that bonobos showed a surprising attraction to others they saw acting in selfish or hurtful ways. The findings suggest that bonobos are drawn to high-status individuals—and, like humans, may see boorish behavior as evidence of power. Evolutionary anthropologists Christopher Krupenye and Brian Hare showed a group of 24 bonobos a series of videos depicting colorful animated figures with googly eyes—similar to the type of cartoon a tired parent might play to distract a toddler for a few minutes.
You can watch the videos here. While we don't have a complete fossil record for humans or chimps, scientists have combined fossil evidence with genetic and behavioral clues gleaned from living primates to learn about the now-extinct species whose descendants would become humans and chimps. Scientists think this creature looked more like a chimpanzee than a human, and it probably spent most of its time in the canopy of forests dense enough that it could travel from tree to tree without touching the ground, Isbell said.
Scientists think ancestral humans began distinguishing themselves from ancestral chimps when they started spending more time on the ground.
Perhaps our ancestors were looking for food as they explored new habitats, Isbell said. It was more recently — maybe 3 million years ago — that these ancestors' legs began to grow longer and their big toes turned forward, allowing them to become mostly full-time walkers. They would have had to travel more on the ground in places where trees were more spread out.
Zinda fishing for termites in Gombe National Park, Tanzania. In her research, Dr. Goodall made a revolutionary discovery when she observed that the chimps in Gombe were making and using tools. It was groundbreaking because it meant redefining everything that scientists thought they knew about what separated humans and chimpanzees! It has also lead to the revelation that other animals also make and use tools, have emotions, intelligence and sentience.
Want to know more and to support our ongoing research in Gombe, now the longest running wild chimpanzee study in the world? Become a Gombe Science Hero!
Find out more and get involved here. The Jane Goodall Institute is a global community conservation organization that advances the vision and work of Dr.
Jane Goodall. By protecting chimpanzees and inspiring people to conserve the natural world we all share, we improve the lives of people, animals and the environment. Everything is connected—everyone can make a difference. She has been passionate about the environment and conservation since her parents raised her spending summers camping in the U.
S National Parks. She hopes to someday work around the world on women's issues and environmental conservation. Upon her graduation in May she would like to become the proud owner of a dog. Donate Get Updates. Share this:. Sometimes we obtain postmortem brain tissue from our closest ancestral relatives.
We can measure the magnitude of gyrations in the cortex and explore specific ideas or hypotheses about how they may be important. In addition, we have fossil crania to study and, from those skulls, we can build casts or make CT scans to get an idea of how the brain size was changing, again building our theories based on these measurements and the correlations that exist.
Furthermore, we have cultural icons as well that give us an idea of how far a species had emerged, given its ability to build, plan, and generate art. In each case, we have material that we can work with: genetic material, tissues, organs, and cultural artifacts. What has been missing, however, is living tissue from some of our lost ancestors and from our closest relatives, like chimps and bonobos.
We have established a bank of cellular tissues from many of our closest relatives that allows us to look at distinctions between ourselves and our closest relatives. As Pascal mentioned, chimpanzees and bonobos are our closest relatives, with 95 percent of our genomes being similar; yet, there are vast differences in phenotype. How can we begin to understand the cellular and molecular mechanisms responsible for these differences? One of the things we can do is take somatic cells, such as blood cells or skin cells, from all of our closest relatives.
Through a process called reprogramming — by overexpression of certain genes in these cells — we can turn the skin or somatic cell into a primitive cell, called an induced pluripotent stem iPS cell. These primitive cells are in a proliferating, living state that can be differentiated to form, in a dish, any cell of the body, allowing us, for the first time, to form living neurons or living heart cells from all of our closest relatives and then compare them across species.
These iPS cells represent a primitive state of development prior to the germ cell. So any change detected in these iPS cells will be passed along to their progeny through the germ cell and into their living progeny.
Now a little bit of a disclaimer for those of us who work in this field: these cells have limitations. They are cells in culture. We cannot really look at social experience, and their relevance to a living organism is oftentimes questionable. But we can ask the question: are there differences that are detectable at a cellular and molecular level that help us understand the origin of humans? We have begun building a library with other collaborators around the world, and have reprogrammed somatic cells from many of these species into iPS cells.
They retain common features of embryonic stem cells at the cellular level and they have the same genetic makeup as predicted based on the species. In our first attempt to see if we could identify differences in these primitive cells, we did what is called a complete transcriptional mRNA analysis.
If we compare the transcriptional genomes of chimpanzees and bonobos, there are very few differences. So we pooled all our animals together and compared that combined nonhuman primate group to the human group.
In analyzing these genomes, we detected two very interesting genes. Why are we interested in these two proteins? These two proteins are active suppressors of the activity of what we call mobile elements, which are genetic elements that exist in all of our genomes. In fact, 50 percent of the DNA in human genomes is made up of these mobile elements molecular parasites of the genome. So what are mobile elements? They are elements that exist in specific locations in the genome and, through unique mechanisms, they can make copies of themselves and jump from one part of the genome to another.
Barbara McClintock discovered these elements through her work on maize. Some of us study a specific form of mobile elements called a LINE-1 retrotransposon.
They exist in thousands of copies in the genome, as a DNA that makes a strand of RNA and then makes proteins that binds back onto the RNA, helping the element copy itself. This combination of mRNA and proteins then moves back into the nucleus where the DNA resides and pastes itself into the genome at a new location.
These LINE elements continue to be active in our genome, and they are particularly active in neural progenitor cells. Not only do humans make more of these proteins, but as an apparent consequence, the lower levels of these L1 suppressors in chimpanzees and bonobos means the L1 elements are much more active in chimpanzees and bonobos than in humans.
When searching the DNA libraries genomes that have been sequenced for chimps, bonobos, and humans, there are many more L1 DNA elements in the genomes of chimps and bonobos relative to humans. This greater number of L1 elements in non-human primate genomes leads to an increase in DNA diversity and, thus, in the diversity of their offspring and potentially in their behavior.
This led us to speculate that this decrease in genetic diversity that occurs in humans leads to a greater dependence on cultural adaptive changes to survive as a species rather than genetic adaptive changes. For example, if a virus were to infect a chimp or a bonobo population, in order for that species to survive it would require a member of the species with the genetic mutation that provided protection in some form from the virus.
Humans do not wait for the mutation from a member of the species that would provide protection from the virus. We build hospitals, we design antibodies, we transmit our knowledge through cultural information cultural evolution rather than relying on genetics genetic evolution for the spread and the survival of the species. I n the s, my research group happened to discover the first known genetic difference between humans and chimpanzees.
And so I thought, well, they must be just like us.
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