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14/03/2017

Redefining 'species'
New species concept based on mitochondrial, nuclear DNA coadaptation

What is a species? Biologists -- and ornithologists in particular -- have been debating the best definition for a very long time. A new commentary published in The Auk: Ornithological Advances proposes a novel concept: that species can be defined based on the unique coadaptations between their two genomes, one in the nuclei of their cells and the other in their mitochondria.

All animals have two sets of genes, one in the cell nucleus and one in organelles called mitochondria, and these two sets of DNA work together to enable cellular respiration and energy production. If they're mismatched, the result is reduced energy output and increased production of damaging free radicals. While the most commonly used species definition is based on the idea that isolated populations slowly accumulate changes in their nuclear genes that make interbreeding impossible, Auburn University's Geoffrey Hill proposes a new twist on the species concept -- that speciation is really the divergence of sets of coadapted mitochondrial and nuclear genes. Interspecies hybrids, his theory suggests, have reduced fitness due their mismatched genomes' reduced ability to work together in the cell.

Past studies have shown that mitochondrial genotype tends to be very good at showing species boundaries between birds. This "mitonuclear compatibility species concept" helps explain the fact that the abrupt transitions between mitochondrial genotypes at species boundaries correspond with abrupt transitions in songs, plumage patterns, and female mating preferences. Interestingly, two closely related species that have recently been documented to have extensively intermingled nuclear genes -- Blue-winged and Golden-winged warblers -- also show an abrupt transition in mitochondrial genes.

"Almost all ornithologists who write and think about avian speciation study phylogeography -- the geographical distribution and genetic structure of bird populations," says Hill. "In contrast, I study bird ornamentation and, particularly, bird coloration. It was the discovery that ornaments signal mitochondrial type that led to my sudden realization that mitochondrial type -- or, more accurately, coadapted sets of mitochondrial and nuclear genes -- define species boundaries. I don't think I would have ever seen the pattern if I had come at the question from a phylogeographic perspective."

"This is an intriguing and controversial idea -- that mitonuclear incompatibilities could be so central to generating new avian species -- and I see this as a call for more research into how these incompatibilities might manifest themselves in young species," says avian evolutionary biologist David Toews of Cornell University. "The functional aspects of mitochondrial genes have, in particular, received little attention from the ornithological community, and it will be interesting to see how these ideas play with additional empirical studies going forward."

Story Source:

Materials provided by American Ornithological Society Publications Office

14/03/2017

Five new synthetic yeast chromosomes assembled
30% of organism's genetic material swapped for engineered replacements

A global research team has built five new synthetic yeast chromosomes, meaning that 30 percent of a key organism's genetic material has now been swapped out for engineered replacements. Like computer programmers, scientists add swaths of synthetic DNA to -- or remove stretches from -- human, plant, bacterial or yeast chromosomes in hopes of averting disease, manufacturing medicines, or making food more nutritious.

A global research team has built five new synthetic yeast chromosomes, meaning that 30 percent of a key organism's genetic material has now been swapped out for engineered replacements. This is one of several findings of a package of seven papers published March 10 as the cover story for Science.

Led by NYU Langone geneticist Jef Boeke, PhD, and a team of more than 200 authors, the publications are the latest from the Synthetic Yeast Project (Sc2.0). By the end of this year, this international consortium hopes to have designed and built synthetic versions of all 16 chromosomes -- the structures that contain DNA -- for the one-celled microorganism, Baker's yeast (S. cerevisiae).

Like computer programmers, scientists add swaths of synthetic DNA to -- or remove stretches from -- human, plant, bacterial or yeast chromosomes in hopes of averting disease, manufacturing medicines, or making food more nutritious. Baker's yeast have long served as an important research model because their cells share many features with human cells, but are simpler and easier to study.

"This work sets the stage for completion of designer, synthetic genomes to address unmet needs in medicine and industry," says Boeke, director of NYU Langone's Institute for Systems Genetics. "Beyond any one application, the papers confirm that newly created systems and software can answer basic questions about the nature of genetic machinery by reprogramming chromosomes in living cells."

In March 2014, Sc2.0 successfully assembled the first synthetic yeast chromosome (synthetic chromosome 3 or synIII) comprising 272,871 base pairs, the chemical units that make up the DNA code. The new round of papers consists of an overview and five papers describing the first assembly of synthetic yeast chromosomes synII, synV, synVI, synX, and synXII. A seventh paper provides a first look at the 3D structures of synthetic chromosomes in the cell nucleus.

Many technologies developed in Sc2.0 serve as the foundation for GP-write, a related initiative aiming to synthesize complete sets of human and plant chromosomes (genomes) in the next ten years. GP-write will hold its next meeting in New York City on May 9-10, 2017.

Global Production

To begin synthesizing a yeast chromosome, researchers must first plan thousands of changes, some of which empower them to move around pieces of chromosomes in a kind of fast, high-powered evolution. Other changes remove stretches of DNA code found to be unlikely to have a functional role by past efforts. Libraries of altered yeast strains can then be screened to see which have the most useful features.

With the edits made, the team starts to assemble edited, synthetic DNA sequences into ever larger chunks, which are finally introduced into yeast cells, where cellular machinery finishes building the chromosome. A major innovation captured in the current round of papers involves this last step.

Previously, researchers were required to finish building one piece of a chromosome before they could start work on the next. Sequential requirements are bottlenecks, says Boeke, which slow processes and increase cost. The current round of papers features several efforts to "parallelize" the assembly of synthetic chromosomes.

Labs around the globe each synthesized different pieces in strains of yeast that were then mated (crossed) to quickly yield thriving yeast, not just with an entire synthetic chromosome, but in some instances with more than one. Specifically, a paper led by author Leslie Mitchell, PhD, a post-doctoral fellow from Boeke's lab at NYU Langone, described the construction of a strain containing three synthetic chromosomes.

"Steps can be accomplished at the same time in many locales and then assembled at the end, like networking laptops to create a global super computer," says Mitchell.

Along the way, the global team honed a number of innovations and came to understand yeast biology better. A team at Tsinghua University, for instance, led an effort where six teams built in pieces synthetic chromosome XII (synXII), which was then assembled into a final molecule more than a million base pairs (a megabase) in length. This largest synthetic chromosome to date is still 1/3,000 of what would be needed to build a human genome molecule, so new techniques will be needed.

In addition, experiments demonstrated that drastic changes can be made to the genomes of yeast without killing them, says Boeke. Yeast strains, for instance, survived experiments where sections of DNA code were moved from one chromosome to another, or even swapped between yeast species, with little effect. Genetically pliable (plastic) organisms make good platforms for the dramatic engineering that may be needed for future applications.

The package of seven newly published had authors from ten universities in several countries, including the US (NYU Langone, Johns Hopkins), China (Tianjin, Tsinghua), France (Institut Pasteur, Sorbonne Universités), and Scotland (Edinburgh); along with authors from key industry partners: BGI, the leading Chinese genomics organization, US/China-based Genescript, and WuXi Qinglan Biotechnology, Inc.

Led by the School of Chemical Engineering and Technology at Tianjin University in China, the paper describing the synthesis of SynV is noteworthy in that is was done by undergraduate students as part of "Build-a-Genome China," a class first taught in the United States at Johns Hopkins, where Boeke worked before coming to NYU Langone. This is part of an emerging global network of "chromosome foundries," says Boeke, "which is building the next generation of synthetic biologists along with chromosomes."

In addition to Boeke and Mitchell, lead organizers for the current studies included Ying-Jin Yuan of Tianjin University, Junbiao Dai of Tsinghua University, Joel Bader from Johns Hopkins, Romain Koszul at the Institut Pasteur, Yizhi Cai at the University of Edinburgh, and Huanming Yang at BGI. The US studies were supported principally by the National Science Foundation. Other key funding sources were the China National High Technology Research and Development Program, Ministry of Science and Technology of the People' Republic of China, National Natural Science Foundation of China, the UK Biotechnology and Biological Sciences Research Council, and ERASynBio.

Story Source:

Materials provided by NYU Langone Medical Center / New York University School of Medicine.

14/03/2017

Biologists identify ancient stress response in corals

Monitoring a newly discovered group of genes in coral could predict when they are under stress and might bleach. The approach could improve conservation strategies for at-risk coral reefs, say scientists.

Stanford marine biologists have discovered that corals activate a specific group of ancient, defensive genes when exposed to stressful environmental conditions. These stress-induced genes could serve as a kind of warning sign for coral bleaching events.

In the study, researchers monitored three coral colonies in a lagoon on Ofu Island, American Samoa, for their response to stressors like high temperatures, oxygen, and ocean acidity. On the hottest days, the researchers saw a significant change in which genes the corals were activating within their cells.

"They started using a whole set of genes that they had just not been using before," said Steve Palumbi, a professor of marine sciences, director of Hopkins Marine Station, and an author of the paper that outlines the study, recently published in Science Advances.

A snapshot of coral health

In 2016, the Great Barrier reef saw the worst coral bleaching event on record as corals across hundreds of miles turned stark white. These bleaching events can eventually lead to coral death. Scientists predict that global climate change and the continued increase in ocean temperatures will increase the frequency of coral bleaching worldwide. The tricky part is, corals don't show visible signs of bleaching beforehand. The genes identified in this study could give scientists a snapshot indication of coral health -- and an idea of when bleaching is likely to occur.

Under stressful conditions, a coral's normal cellular functions begin to fail. In response, the group of genes identified in this study triggers a process, called the unfolded protein response, that works to restore normal conditions within the cell. If conditions continue to worsen, the corals bleach and eventually die.

"For the first time, we are able to ask those corals, 'how are you doing?' They don't have a heartbeat. They don't have a pulse. We need to know their vital signs in order to understand how they react to the environment," Palumbi said.

An ancient stress response

Over the course of the seventeen-day study period, Palumbi and graduate student Lupita Ruiz-Jones monitored over 17,000 coral genes at just after noon each day. On the seventh and eighth day, when tides were lowest and temperatures hottest, the corals' genes initiated the cellular unfolded protein response. On day nine, the tides rose and the corals' systems returned to normal.

"This response just shows how in sync corals are with their environment," said Ruiz-Jones, who was first author on the paper.

This stress response is not unique to corals. It's been observed in mammals as well as some yeast species. Humans activate the same ancient genes in response to diseases, like cancer. In times of stress, a cell's misfolded and unfolded proteins accumulate in the endoplasmic reticulum, a series of flattened, tube-like structures in the cell that assist with building proteins. The unfolded protein response is a reaction to the flood of misassembled proteins.

"It's basically the organism recognizing that something isn't right," Ruiz-Jones said.

Studying tough corals

The lagoon on Ofu Island, a shallow turquoise bathtub, provided the ideal coral laboratory for studying heat-tolerant corals. The corals on Ofu Island experience water temperatures near human body temperature, enough to kill most coral species. The corals of Ofu, however, prosper in stressful environmental conditions.

Scientists believe that frequent, pulsing exposure to high temperatures may make corals stronger, much in the same way athletes train for competition. Understanding why some of the world's toughest corals are so heat-tolerant could help scientists identify and map other survivor coral colonies around the globe.

"We know that corals have the ability to adapt and evolve to warmer water than we thought before. We can use that as a primary asset to help them live through the next decades until we solve global climate change," Palumbi said.

Palumbi is also a senior fellow at the Stanford Woods Institute for the Environment.

Story Source:

Materials provided by Stanford University.

14/03/2017

Surprise: Transport proteins evolved long before their compounds emerged

As in an arms race plants constantly develop new toxic compounds to protect themselves against herbivores and diseases -- and as in war, mobility is important. Therefore, plants evolved transport proteins to efficiently and timely concentrate toxic defense compounds where they are needed the most.

"It's an exciting discovery because it's often assumed that evolution is guided by what gives the organism an advantage. Why then were these transporters maintained during evolution when the compounds they move had not yet emerged?" says Associate Professor Hussam Nour-Eldin.

Discovery spikes international interest

The scientists investigated how transport proteins evolved along with the emergence of new defense compounds. The research goal was to understand how transport proteins acquire the ability to move new toxic compounds -- and what comes first in the evolution: the transport protein's ability to move a defense compound or the compound?

First-author Morten Egevang Jørgensen, says the team was surprised to find that proteins with the ability to transport new defense compounds may have evolved before the compounds had even occurred in nature.

Recently, the international life science and biomedical journal eLife published the research as the results are of great importance to our understanding of how transport proteins evolve the ability to transport new compounds.

Chicken or the egg?

The scientific question is in other words a "the chicken or the egg" challenge. Until now it was generally assumed that toxic compounds have to emerge in nature before the need to transport them arises.

However, as the research shows, transport proteins can emerge long before the compounds have seen daylight.

Jørgensen explains that it might be that the earliest transport proteins are able to move several different toxic compounds (including some that does not yet exist in nature) and only later -- when the new toxic compounds have emerged in nature -- do the transport proteins emerge that specifically are responsible for transporting the new toxic compounds.

"Now we seek to understand how these transport proteins have been able to survive the natural selection until their compounds emerge," continues Nour-Eldin.

1 billion people may get a non-toxic cassava tuber to eat

The results are not only exciting to those interested by basic research and evolution.

The study has also generated valuable knowledge on how crops containing toxic compounds in edible parts could be made healthier.

During the research, the scientists succeeded in identifying the proteins responsible for transporting the toxic compounds in the cassava plant. Cassava is an essential source of food for up to 1 billion people but the roots contain large amounts of hydrogen cyanide.

"Now that we have identified the transport proteins that are able to move these toxic compounds we may be able to prevent accumulation of them in the edible plant roots," says Professor Barbara Ann Halkier, Head of the DynaMo Center and part of the team, and continues "In the long term, the results may improve food quality."

Story Source:

Materials provided by Faculty of Science - University of Copenhagen.

14/03/2017

Cross-species jumps may play unexpectedly big role in virus evolution

On occasion, a virus may jump from one host species to another and adapt to the new host. Such cross-species transmission happens more often than expected, according to new research, and it may play a much bigger role in virus evolution than previously thought.

On occasion, a virus may jump from one host species to another and adapt to the new host. Such cross-species transmission happens more often than expected, according to new research published in PLOS Pathogens, and it may play a much bigger role in virus evolution than previously thought.

Understanding how viruses evolve and how often they jump to new hosts is important for studying emerging viral diseases. Scientists have hypothesized that viruses usually co-diverge with their hosts, forming new viral species as their hosts evolve into new species. It has been assumed that cross-species jumps are relatively rare and contribute less to virus evolution.

To better understand how viruses evolve, Jemma Geoghegan of the University of Sydney, Australia, and colleagues compared the evolutionary histories of viruses and host species. Previous studies had focused on narrow groups of viruses; for a broader picture, Geoghegan's team studied 19 virus families that infect a variety of hosts, including mammals, birds, reptiles, amphibians, fish, plants, and insects.

The researchers began with branching "tree" diagrams that illustrated the evolutionary history of each virus family and its host species. Like family trees, these evolutionary trees trace the lineage of species back through common ancestors that later evolved into new species.

The scientists then used a previously developed method to compare the evolutionary trees of viruses and hosts. The method measures similarity between trees; co-divergence results in host and virus trees with similar branching patterns, as the virus evolves alongside the host. Meanwhile, cross-species jumps result in dissimilar host and virus trees, as new viruses evolve and jump from host to host.

The scientists found that cross-species transmission has played a central role in evolution for all 19 virus families, while co-divergence is relatively rare. Cross-species jumps were especially frequent in virus families whose genetic material is encoded in RNA rather than DNA. The findings also revealed which virus families may be more likely to jump hosts and evolve to infect new species.

'An important implication from our work is that the more new viruses we discover, then the more examples of species jumping we are likely to see' said project leader Professor Edward Holmes from the University of Sydney. 'Jumping hosts is the way many RNA viruses live their life' he continued.

This research was performed at the level of virus families, and not for individual viral species. Further studies with larger datasets could help confirm the findings and provide further insight into virus evolution.

Story Source:

Materials provided by PLOS.

14/03/2017

Dampened immunity during pregnancy promotes evolution of more virulent flu...

During pregnancy, a mother's immune system is suppressed to protect the fetus, which is perceived as a foreign body because it is genetically different. A study in mice found that suppressed immunity during pregnancy creates a window of opportunity for the H1N1 influenza virus to infect the mother and to rapidly, within a few days, mutate into a more virulent strain.

A study in mice found that suppressed immunity during pregnancy creates a window of opportunity for the H1N1 influenza virus to infect the mother and to rapidly, within a few days, mutate into a more virulent strain. The findings appear in Cell Host & Microbe on March 8. More research is required to determine if similar viral mutations occur in pregnant humans.

"The first line of defense of the immune system, the innate immune response, is not acting quickly enough to clear the virus," says co-lead author Gülsah Gabriel, a virologist at the Heinrich Pette Institute, Leibniz Institute for Experimental Virology in Hamburg, Germany. "The virus takes advantage of this permissive environment and mutates very fast. This is what influenza viruses do best. The new variants are responsible for increased virulence."

For the last century, study after study has shown that pregnant women suffer more severely from influenza than non-pregnant women. A 2010 World Health Organization analysis of the 2009 H1N1 influenza pandemic found that pregnant women were 7 times more likely to be hospitalized and twice as likely to die from H1N1 infection than non-pregnant women.

In response, Gabriel and co-lead author Petra Clara Arck, a reproductive immunologist at the University Medical Center in Hamburg, joined forces to understand the biology behind these observations. Previous studies of influenza evaluated mice that were pregnant with genetically identical fetuses, called syngenic pregnancies. These pregnancies do not mimic natural human pregnancies, in which babies are the product of the combined genes of a mother and father.

So, using mice, Gabriel and Arck also studied allogenic pregnancies, in which the fetuses differ genetically from the mother. In allogenic pregnancies, they found that the immune system is more suppressed than in syngenic pregnancies.

The immune system typically mounts waves of defense against viral infections. Cells in the innate immune system respond immediately by secreting inflammatory factors called cytokines to stop the spread of infection. As the infection progresses, adaptive immune cells called T cells move to the area of infection, where they detect and kill infected cells.

To understand immune suppression in mice with genetically distinct pregnancies, the researchers examined gene expression patterns in immune cells during infection. They found that the genes responsible for releasing cytokines were suppressed, resulting in a weak initial response to infection. In addition, genes responsible for activating and recruiting T cells to an infection were also suppressed. "The entire immune system is damped down to protect the fetus," says Arck.

Influenza appears to take immediate advantage of the mother's vulnerability, according to the study. During the first days of infection, a typical innate immune response will stop the spread. But during pregnancy, the initial response is not strong enough to stop the virus. Rather, surviving viral invaders have time to mutate and produce a range of variants, some of which are more likely to cause a severe infection.

The most frequent mutation the researchers found in influenza in pregnant mice was a variant that further dampens the innate immune response, giving the virus an even better chance to survive and thrive. "In this environment of a dampened innate immune system, the virus has a chance to escape and become more virulent," says Gabriel. "This suggests that during pregnancy, a typical influenza infection could hit very hard."

To determine if pregnant women experience a similar evolution of influenza infection, Gabriel and Arck are planning to look for similar mutations in samples from pregnant women who suffered from influenza. Similar mutations have been seen in other influenza cases in pregnant women, but not in studies large enough to confirm that they are more frequent than other variants.

If a larger study confirms that these variants are seen more commonly in pregnant women, that would further strengthen the importance of influenza vaccinations for pregnant women. "The best bet for pregnant women is to be vaccinated to prevent infection, because influenza viruses are very good at escaping," says Gabriel.

In response to the 2009 H1N1 influenza pandemic, the World Health Organization made pregnant women the number one priority for vaccination, with a goal of vaccinating 75% of this population. The flu shot is safe and protects both the mother and the fetus from infection. According to the CDC, in the US in 2016, about 50% of pregnant women got the flu shot, an improvement over the 20% vaccinated in 2009.

Story Source:

Materials provided by Cell Press.

14/03/2017

Ancient southern China fish may have evolved prior to the 'Age of Fish'

An ancient fish species with unusual scales and teeth from the Kuanti Formation in southern China may have evolved prior to the 'Age of Fish', according to a new study.

An ancient fish species with unusual scales and teeth from the Kuanti Formation in southern China may have evolved prior to the "Age of Fish," according to a study published March 8, 2017 in the open-access journal PLOS ONE by Brian Choo from Flinders University, Australia, and colleagues at the Institute of Vertebrate Paleontology and Paleoanthropology, China.

The Devonian Period (419.2 -- 358.9 million years ago) is popularly called the "Age of Fishes" because of the apparent increase in the abundance and variety of jawed fishes when compared with the preceding Silurian Period (443.7 -- 419.2 million years ago). Until recently, the Silurian fossil record of jawed vertebrates has been based on highly fragmentary remains, limiting our understanding of their early evolution. Recent discoveries from the Kuanti Formation of Yunnan, southwestern China, have dramatically enhanced our knowledge, with several superbly preserved fish species described in recent years. The fish-bearing sediments of the Kuanti Formation have been dated to the latter part of the Silurian, about 423 million years ago.

Now, Choo and colleagues have described a new genus and species of Kuanti fish, Sparalepis tingi, which represents only the second Silurian bony fish based on more than isolated fragments. This new form, along with its contemporary Guiyu and the slightly more recent Psarolepis, possesses spine-bearing pectoral and pelvic girdles, features once thought to be restricted to the armored placoderm fishes. Sparalepis and its kin may represent an early radiation of stem-sarcopterygians, ancient cousins of modern lungfish, coelacanths and tetrapods.

But Sparalepis also has an unusual scale morphology which distinguishes it from its cousins. The scales are particularly tall, thick and narrow, with the ones at the front having interlocking mechanisms on both the outer and inner surfaces. The closely packed squamation resembles a wall of shields, giving rise to the genus name of Sparalepis, a mixture of ancient Persian and Greek meaning "shield scale."

Sparalepis adds to an ever-growing list of bizarre ancient fishes from the Silurian and earliest Devonian of Yunnan, suggesting that this region may have been an early center of diversification for the jawed vertebrates. The "Age of Fishes" appears to have arrived early during the Silurian of southern China.

Story Source:

Materials provided by PLOS.

14/03/2017

Behavioral biology: Ripeness is all

In contrast to other members of the Drosophila family, the spotted-wing fly D. suzukii deposits its eggs in ripe fruits. Biologists have now elucidated the sensory basis of their ability to exploit a novel ecological niche.

In contrast to other members of the Drosophila family, the spotted-wing fly D. suzukii deposits its eggs in ripe fruits. Biologists from Ludwig-Maximilians-Universitaet (LMU) in Munich have now elucidated the sensory basis of their ability to exploit a novel ecological niche.

Unlike most species of the genus Drosophila, which deposit their eggs in fermenting fruits, the so-called spotted-wing Drosophila, D. suzukii, lays its eggs in ripe fruits. This apparently minor difference in behavior can have catastrophic consequences for commercial fruit-growers, and has made the species into a crop pest. For the puncture made by the female's ovipositor facilitates infections, while the hatched larvae feed on the fruit pulp. As a result, these infestations cause enormous damage to soft-fruit crops, such as cherries, raspberries, grapes and strawberries. LMU biologists led by Professor Nicolas Gompel, in a collaboration with the groups of Dr. Benjamin Prud'homme (CNRS, France) and Professor Ilona Grunwald Kadow (Technical University, Munich), have begun to explore the genetic basis for this unusual egg-laying behavior. Their findings appear in the latest issue of the journal Current Biology.

The researchers combined behavioral tests and genetic methods to determine how the closely related drosophilid species D. melanogaster, D. biarmipes and D. suzukii go about choosing the ideal nursery for their brood, each in their own way. The experiments showed that, in the search for egg-laying sites, the flies respond to the texture of the fruit, to the chemical composition of the surface and to characteristic odor compounds. In other words, they use the senses of smell, touch and taste. D. melanogaster females lay their eggs exclusively in overripe and decaying fruits. In contrast, D. suzukii responds to the volatile chemicals emitted by freshly ripened fruits, and prefers the firm texture of their skins. D. biarmipes females are less choosy and therefore more versatile. Unlike D. melanogaster, they are not restricted to rotting fruits. However, because of the anatomy of their ovipositor, they are only able to deposit their eggs in fruits that have been damaged or otherwise softened up.

"We conclude from our findings that, in the course of evolution, the female perceptual system in D. suzukii females has been progressively remodeled, allowing the flies to detect and preferentially respond to stimuli that are typical of ripe rather than overripe fruits," says Gompel. "The flies can exploit this ecological niche because they have a larger and sturdier ovipositor, which is capable of penetrating the tougher skins of ripe fruits. And the behavioral modification developed in concert with the alteration in the egg-laying apparatus," says Gompel. "In addition, we believe that the enlarged ovipositor was a secondary acquisition -- comparable to the adaptive change in the morphology of the teeth in mammals, which was also initiated in response to an alteration in diet."

The researchers now plan to study the genetic basis for the changes in the spotted-wing Drosophila's perceptual systems. "These may well include mutations in genes that code for sensory receptors," Gompel suggests. "In that case, we will also have to ask how such changes affected the functions and connectivity of the nerve cells involved."

Story Source:

Materials provided by Ludwig-Maximilians-Universitaet Muenchen (LMU).

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