Lifeboat Foundation

About 99 percent of human genes are shared with chimpanzees. Only the small remainder sets us apart. However, we have one important difference: The brain of humans is three times as big as the chimpanzee brain.

During evolution our genome must have changed in order to trigger such brain growth. Wieland Huttner, Director and Research Group Leader a the Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), and his team identified for the first time a gene that is only present in humans and contributes to the reproduction of basal brain stem cells, triggering a folding of the neocortex. The researchers isolated different subpopulations of human brain stem cells and precisely identified, which genes are active in which cell type. In doing so, they noticed the gene ARHGAP11B: it is only found in humans and in our closest relatives, the Neanderthals and Denisova-Humans, but not in chimpanzees. This gene manages to trigger brain stem cells to form a bigger pool of stem cells. In that way, during brain development more neurons can arise and the cerebrum can expand. The cerebrum is responsible for cognitive functions like speaking and thinking.

Wieland Huttner’s researchers developed a method that isolates and identifies special subpopulations of brain stem cells from the developing human cerebrum. No one has managed to do this so far. The scientists first isolated different stem and progenitor cell types from fetal mice and human cerebrum tissue. In contrast to the big and folded human brain, the brain of mice is small and smooth. After the isolation, the researchers compared the genes that are active in the various cell types and were able to identify 56 genes that are only present in humans and which play a role in brain development. “We noticed that the gene ARHGAP11B is especially active in basal brain stem cells. These cells are really important for the expansion of the neocortex during evolution,” says Marta Florio, PhD student in Wieland Huttner’s lab, who carried out the main part of the study.

The neocortex is the part of the brain that enables us to speak, dream, or think. The underlying mechanism that led to the expansion of this brain region during evolution, however, is not yet understood. A research team headed by Wieland Huttner, director at the Max Planck Institute of Molecular Cell Biology and Genetics, now reports an important finding that paves the way for further research on brain evolution: The researchers analyzed the gyrencephaly index, indicating the degree of cortical folding, of 100 mammalian brains and identified a threshold value that separates mammalian species into two distinct groups: Those above the threshold have highly folded brains, whereas those below it have only slightly folded or unfolded brains. The research team also found that differences in cortical folding did not evolve linearly across species.

The Dresden researchers examined brain sections from more than 100 different mammalian species with regard to the gyrencephaly index, which indicates the degree of folding of the neocortex. The data indicate that a highly folded neocortex is ancestral – the first mammals that appeared more than 200 million years ago had folded brains. Like brain size, the folding of the brain, too, has increased and decreased along the various mammalian lineages. Life-history traits seem to influence this: For instance, mammals with slightly folded or unfolded brains live in rather small social groups in narrow habitats, whereas those with highly folded brains form rather large social groups spreading across wide habitats.

A threshold value of the folding index at 1.5 separates mammalian species into two distinct groups: Dolphins and foxes, for example, are above this threshold value – their brains are highly folded and consist of several billion neurons. This is so because basal progenitors capable of symmetric proliferative divisions are present in the neurogenic program of these animals. In contrast, basal progenitors in mice and manatees lack this proliferative capacity and thus produce less neurons and less folded or unfolded brains.

Animal studies on great apes have long been banned in Europe for ethical reasons. For the question pursued here, organoids (three-dimensional cell structures a few millimeters in size that are grown in the laboratory) are an alternative to animal experiments. These organoids can be produced from pluripotent stem cells, which then differentiate into specific cell types, such as nerve cells. In this way, the research team was able to produce both chimpanzee brain organoids and human brain organoids. “These brain organoids allowed us to investigate a central question concerning ARHGAP11B,” says Wieland Huttner of the MPI-CBG, one of the three lead authors of the study published in EMBO Reports.

“In a previous study we were able to show that ARHGAP11B can enlarge a primate brain. However, it was previously unclear whether ARHGAP11B had a major or minor role in the evolutionary enlargement of the human neocortex,” says Wieland Huttner. To clarify this, the ARGHAP11B gene was first inserted into brain ventricle-like structures of chimpanzee organoids. Would the ARGHAP11B gene lead to the proliferation of those brain stem cells in the chimpanzee brain that are necessary for the enlargement of the neocortex?

“Our study shows that the gene in chimpanzee organoids causes an increase in relevant brain stem cells and an increase in those neurons that play a crucial role in the extraordinary mental abilities of humans,” said Michael Heide, the study’s lead author, who is head of the Junior Research Group Brain Development and Evolution at the DPZ and employee at the MPI-CBG.

In a recent study, scientists have made an unprecedented discovery: crows are not only clever; they also show consciousness and are aware of the world around them. This means they also have experiences that they feel and remember.

As per the research work published in the journal ‘Science’, researchers have discussed that crows show a primary or sensory consciousness. Such a form of consciousness was previously only found among primates before. This was the first time such a form of consciousness was recorded among a bird. Scientists believe this study will pave the path for researchers to understand better the evolution of awareness among the different living beings and how it affects the brain and thinking capacity among the various organisms.

It is difficult to understand the extent of consciousness, especially concerning birds because they do not speak the way we do, nor do we have sophisticated instruments to understand what goes inside their heads. Consciousness involves the thought process behind self-awareness and awareness of the world around oneself. With a good conscience, an individual often shows problem-solving traits and good decision-making skills – some visible strategies, both at which crows are good.

Most neurons in the human brain are generated from neural stem cells during embryonic development. After birth, a small reservoir of stem cells remains in the brain that keeps on producing new neurons throughout life. However, the question arises as to whether these new neurons really support brain function? And if so, can we improve brain capacity by increasing the number of neurons? The research group of Prof. Federico Calegari at the Center for Regenerative Therapies Dresden (CRTD) of TU Dresden has answered these questions, now published in the EMBO Journal.

In their latest study, the scientists analysed healthy adult mice in which the small reservoir of stem cells was manipulated in order to increase in number. As a result, the number of neurons, generated from these stem cells, also increased. In mice, these neurons mainly populate the brain area responsible for interpreting odours. In fact, olfaction is one to the most powerful senses in mice, fundamental for finding food and escape from predators. As powerful as the sense of smell naturally is in mice, in the following behavioural experiments the scientists found that mice with more neurons were able to distinguish extremely similar odours that normal mice failed to. Hence, this study is fundamental in proving that stem cells can be used to improve brain function.

“Evolution gave mice an extremely sensitive olfactory system. It is amazing that by adding few neurons we could improve something that seemed already close to perfection,” states Prof. Federico Calegari. “This study sets the basis for our research, which now is focused on finding out whether we could apply our strategy as a therapeutic approach in neurodegenerative models.”

This lecture was recorded on February 3, 2003 as part of the Distinguished Science Lecture Series hosted by Michael Shermer and presented by The Skeptics Society in California (1992–2015).

Can there be freedom and free will in a deterministic world? Renowned philosopher and public intellectual, Dr. Dennett, drawing on evolutionary biology, cognitive neuroscience, economics and philosophy, demonstrates that free will exists in a deterministic world for humans only, and that this gives us morality, meaning, and moral culpability. Weaving a richly detailed narrative, Dennett explains in a series of strikingly original arguments that far from being an enemy of traditional explorations of freedom, morality, and meaning, the evolutionary perspective can be an indispensable ally. In Freedom Evolves, Dennett seeks to place ethics on the foundation it deserves: a realistic, naturalistic, potentially unified vision of our place in nature.

Continue reading “Dr. Daniel Dennett — Freedom Evolves: Free Will, Determinism, and Evolution” »

Where are all the aliens?! This is the essence to the Fermi Paradox. It’s most popular solution is the “Great Filter.” What is the obstacle that life and/or intelligent species are unlikely to survive? Let’s discuss.

00:00 Cold Open.
00:18 Introduction.
00:48 History of the Fermi Paradox.
02:48 Fermi Paradox Explained.
03:55 Drake Equation Explained.
07:04 The Great Filter.
09:56 Rare Earth Hypothesis.
10:53 Geologic Time in Galactic Years.
14:48 Evolution of Intelligent Life.
17:03 Conclusions.
19:11 Poll Results.
19:47 Outro.
20:10 Featured Comment.

Continue reading “Humans are the First Aliens. Here’s Why” »

Scientists have long pondered how and when the evolution of prokaryotes to eukaryotes occurred. A collaborative research team from Tohoku University and the University of Tokyo may have provided some answers after discovering new types of microfossils dating 1.9 billion years.

Details of their findings were published in the journal Precambrian Research on August 19, 2022.

The Gunflint Formation traverses the northern part of Minnesota into Ontario, along the northwestern shores of Lake Superior. The first bacterial microfossils were discovered there in 1954, with Gunflint microfossils now recognized as a “benchmark” in the field of life evolution.

The axolotl (Ambystoma mexicanum) is an aquatic salamander renowned for its ability to regenerate its spinal cord, heart and limbs. These amphibians also readily make new neurons throughout their lives. In 1964, researchers observed that adult axolotls could regenerate parts of their brains, even if a large section was completely removed. But one study found that axolotl brain regeneration has a limited ability to rebuild original tissue structure.

So how perfectly can axolotl’s regenerate their brains after injury?

Continue reading “Axolotls can regenerate their brains, revealing secrets of brain evolution and regeneration” »