Lifeboat Foundation

A study of the mechanical forces in certain immune cells may give new insights into how organisms deal with ever-evolving pathogens.

To fight disease, many organisms have an adaptive immune system, which learns the molecular shapes of foreign elements (antigens) and remembers them to mount a defense against future infections. In vertebrates, the learning stage involves a remarkable cycle of evolution within an individual animal—a cycle called affinity maturation, which involves a type of immune cell called a B cell (Fig. 1). In this process, B cells are selected to have receptors that bind strongly to specific antigens. However, if these cells become too specialized, they risk becoming unresponsive to slightly mutated pathogens. Fortunately, the immune system can limit affinity maturation to retain a range of specificities for target pathogens. Just how the immune system is able to do that is the subject of a fascinating new study by Hongda Jiang and Shenshen Wang from the University of California, Los Angeles [1].

Mathematicians have uncovered a universal explanatory framework that provides a “window into evolution.” This framework explains how molecules interact with each other in adapting to changing conditions while still maintaining tight control over essential properties that are crucial for survival.

According to Dr. Araujo from the QUT School of Mathematical Sciences, the research results provide a blueprint for the creation of signaling networks that are capable of adapting across all life forms and for the design of synthetic biological systems.

“Our study considers a process called robust perfect adaptation (RPA) whereby biological systems, from individual cells to entire organisms, maintain important molecules within narrow concentration ranges despite continually being bombarded with disturbances to the system,” Dr. Araujo said.

Like treasured recipes passed down from generation to generation, there are just some regions of DNA that evolution doesn’t dare tweak. Mammals far and wide share a variety of such encoded sequences, for example, which have remained untouched for millions of years.

Humans are a strange exception to this club. For some reason, recipes long preserved by our ancient ancestors were suddenly ‘spiced up’ within a short evolutionary period of time.

Because we’re the only species in which these regions have been rewritten so rapidly, they are called ‘human accelerated regions’ (or HARs). What’s more, scientists think at least some HARs could be behind many of the qualities that set humans apart from their close relatives, like chimpanzees and bonobos.

Forget about evolution, climate change or vaccines – what makes people really lose their mind, apparently, is cats.

“We’ve had posts that have affected people’s lives in a very substantial way, including posts that went beyond the virtual world. People really got threats or disrespectful comments,” says Yomiran Nissan.

Continue reading “The Israelis bringing us big science in little soundbites” »

Discovery could help plug gaps in understanding of evolution after Cambrian explosion more than 500m years ago.

The research uses the genomes of 241 species.

A species is a group of living organisms that share a set of common characteristics and are able to breed and produce fertile offspring. The concept of a species is important in biology as it is used to classify and organize the diversity of life. There are different ways to define a species, but the most widely accepted one is the biological species concept, which defines a species as a group of organisms that can interbreed and produce viable offspring in nature. This definition is widely used in evolutionary biology and ecology to identify and classify living organisms.

Dr. Rupert Sheldrake believes that memory is inherent to nature, and has spent the last forty years of his career investigating slippery, esoteric phenomena at the very edges of empiricism. Some of the results are intriguing — dogs that know when their owners have started the long journey home, crosswords that become easier to solve a few days after they’ve been published in the papers, IQ scores increase generation after generation. His work is ongoing, the territory marginal, and the implications immense.

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Continue reading “Memory Across Time & Space — Dr. Rupert Sheldrake, Biologist” »

Using Zoonomia’s data, researchers have also constructed a phylogenetic tree that estimates when each mammalian species diverged from its ancestors⁵. This analysis lends support to the hypothesis that mammals had already started evolutionarily diverging before Earth was struck by the asteroid that killed the dinosaurs about 65 million years ago — but that they diverged much more rapidly afterwards.

Only the beginning

The Zoonomia Project is just one of dozens of efforts to sequence animal genomes. Another large effort is the Vertebrate Genomes Project (VGP), which aims to generate genomes for roughly all 71,000 living vertebrate species, which include mammals, reptiles, fish, birds and amphibians. Although the two projects are independent of one another, many researchers are a part of both, says Haussler, who is a trustee of the VGP.

Over the past 100 million years, mammals have adapted to nearly every environment on Earth. Scientists with the Zoonomia Project have been cataloging the diversity in mammalian genomes by comparing DNA sequences from 240 species that exist today, from the aardvark and the African savanna elephant to the yellow-spotted rock hyrax and the zebu.

This week, in several papers in a special issue of Science, the Zoonomia team has demonstrated how comparative genomics can not only shed light on how certain species achieve extraordinary feats, but also help scientists better understand the parts of our genome that are functional and how they might influence health and disease.

In the new studies, the researchers identified regions of the genomes, sometimes just single letters of DNA, that are most conserved, or unchanged, across mammalian species and millions of years of evolution—regions that are likely biologically important. They also found part of the genetic basis for uncommon mammalian traits such as the ability to hibernate or sniff out faint scents from miles away. And they pinpointed species that may be particularly susceptible to extinction, as well as genetic variants that are more likely to play causal roles in rare and common human diseases.