PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Xenacoelomorpha -- a new phylum in the animal kingdom

Xenacoelomorpha -- a new phylum in the animal kingdom
2011-02-17
(Press-News.org) An international team of scientists including Albert Poustka from the Max Planck Institute for Molecular Genetics in Berlin has discovered that Xenoturbellida and the acoelomorph worms, both simple marine worms, are more closely related to complex organisms like humans and sea urchins than was previously assumed. As a result they have made a major revision to the phylogenetic history of animals. Up to now, the acoelomate worms were viewed as the crucial link between simple animals like sponges and jellyfish and more complex organisms. It has now emerged that these animals did not always have as simple a structure as they do today.

The genus Xenoturbella lives off the coast of Scandinavia, Scotland and Iceland. It shares a simple body structure with the acoelomorph worms: these organisms, which reach a maximum size of just a few millimetres, have no through gut, no gill slits and no body cavity (Greek: coelom = cavity). Many members of both groups live on the ocean floor and feed on organic particles in the sediment. Some species live parasitic, e.g. in the intestines of sea cucumbers.

The animal kingdom is divided into different evolutionary lines. These include, among others, the protostomes ("mouth first") and deuterostomes ("second mouth"). In the protostomes, the mouth that develops at the beginning of embryonic development becomes the organism's actual mouth, whereas, in the deuterostomes, it becomes the anus and the mouth develops at a later stage. Three deuterostome phyla were known up to now: the Chordates (e.g. vertebrates), the Echinoderms (sea urchins, starfish, sea cucumbers) and the Hemichordates (e.g. acorn worm). "Our research shows that Xenoturbellida and Acoelomorpha together form the fourth phylum which we have called 'Xenacoelomorpha'," explains Albert Poustka from the Planck Institute for Molecular Genetics in Berlin.

According to the scientists, Xenoturbellida and Acoelomorpha have a shared ancestor, from which the complex group of deuterostomes descend. "Therefore, contrary to what was previously assumed xenacoelomorph worms did not always have a simple structure but lost the characteristics typical for many deuterostomes over the course of evolution. The worms simplified their construction plan in reality because that was clearly as advantageous – or even more advantageous – than a complicated body structure," says Poustka.

With the help of extremely processor-intensive mathematical models, the scientists examined new "mini" genes (microRNAs) and amino acids from the fully sequenced mitochondrial genomes of Acoelomorpha and Xenoturbellida, and a large set of several hundred genes. The analysis of the Xenoturbella microRNAs and the acoelomate worm Hofstenia miamia showed that the previously analysed acoelomate worm Symsagittifera roscoffensis had lost many of these "mini" genes. The gene repertoire of the analysed animals points instead to the kinship between these animals and the deuterostomes. For example, they have a microRNA that was previously only known to exist in echinoderms and acorn worms. Moreover, all of the animals analysed up to now from the new Xenacoelomorpha phylum have the gene RSB66, which could previously only be demonstrated in deuterostomes.

The complex organisms of the protostomes and deuterostomes do not originate both from acoelomorph like worms as was previously assumed. Earlier studies were clearly subject to a systematic error that scientists refer to as the "long branch artefact". This error often arises in the comparison of the genotypes of organisms that have long developed independently of each other. Even if the DNA sequences of some organisms mutated more quickly than the average, this effect can arise. "This was precisely the case with the acoelomorph worms," says Poustka. As a next step the researchers are now decoding the entire genome of the different species of Xenacoelomorpha in order to reach a better understanding of the evolution of the deuterostomes.



INFORMATION:

Original work:
Acoelomorph flatworms are deuterostomes related to Xenoturbella
Hervé Philippe, Henner Brinkmann, Richard R. Copley, Leonid L. Moroz, Hiroaki Nakano, Albert J. Poustka, Andreas Wallberg, Kevin J. Peterson & Maximilian J. Telford
published in online in Nature, February 10th 2011


[Attachments] See images for this press release:
Xenacoelomorpha -- a new phylum in the animal kingdom

ELSE PRESS RELEASES FROM THIS DATE:

Tau-induced memory loss in Alzheimer's mice is reversible

2011-02-17
VIDEO: To test their capacity to learn, the mice are trained to find an underwater platform which is not visible to them from the edge of a water basin. The swimming... Click here for more information. Amyloid-beta and tau protein deposits in the brain are characteristic features of Alzheimer disease. The effect on the hippocampus, the area of the brain that plays a central role in learning and memory, is particularly severe. However, it appears that the toxic effect of tau ...

Insects hold atomic clues about the type of habitats in which they live

2011-02-17
Scientists have discovered that insects contain atomic clues as to the habitats in which they are most able to survive. The research has important implications for predicting the effects of climate change on the insects, which make up three-quarters of the animal kingdom. Applying a method previously only used to examine the possible effects of climate change on plants, scientists from the University of Cambridge can now determine the climatic tolerances of individual insects. Their research was published today, 16 February, in the scientific journal Biology Letters. Because ...

Researchers link gene mutations to Ebstein's anomaly

2011-02-17
Ebstein's anomaly is a rare congenital valvular heart disease. Now, in patients with this disease, researchers of the Academic Medical Center Amsterdam in the Netherlands, the University of Newcastle, UK and the Max Delbrück Center for Molecular Medicine (MDC) Berlin-Buch have identified mutations in a gene which plays an important role in the structure of the heart. The researchers hope that these findings will lead to faster diagnosis and novel, more specifically targeted treatment methods (Circulation Cardiovascular Genetics, DOI: 10.1161/CIRCGENETICS.110.957985)*. Ebstein's ...

Build your online networks using social annotations

2011-02-17
Researchers at Toshiba are working on a way of finding clusters of like-minded bloggers and others online using "social annotations". Social annotations are the tags and keywords, the comments and feedback that users, both content creators and others associate with their content. Their three-step approach could help you home in on people in a particular area of expertise much more efficiently and reliably than simply following search engine results. The same tools might also be used in targeted marketing. Users of photo gallery sites, such as Flickr (http://www.flickr.com/) ...

Water softeners not found to improve childhood eczema

2011-02-17
The first study of its kind in the world — involving 336 children aged between six months and 16 years old — has shown that installing a water softener for three months brings no additional relief for eczema sufferers. Up to one fifth of all children of school age have eczema, along with about one in 12 of the adult population. Anecdotal reports from patients have suggested that hard water may worsen atopic eczema. Population surveys have also suggested a possible link between atopic eczema prevalence and the degree of water hardness. It had been hoped that water softeners ...

Treatment for manic-depressive illness restores brain volume deficits

2011-02-17
Philadelphia, PA, 16 February 2011 - Lithium, introduced in the late 1940's, was the first "wonder drug" in psychiatry. It was the first medication treatment for the manic and depressive episodes of bipolar disorder and it remains among one of the most effective treatments for this disorder. In the past 15 years, as molecular mechanisms underlying the treatment of bipolar disorder began to emerge, basic research studies conducted in animals began to identify neuroprotective and perhaps neurotrophic effects of this important medication. The identification of these ...

Study looks into evolution of breast cancer in Spain

2011-02-17
Pioneering Spanish provinces in terms of early prevention of breast cancer, such as Navarre and the Basque Country, record lower death rates, although the trend is towards the figures levelling out all over Spain. These are the results of a study carried out by Spanish researchers, which analyses the number of women who died between 1975 and 2005. "The Canary Islands, Balearic Islands, some parts of Catalonia, Valencia and Murcia, as well as the south west region, have higher breast cancer death rates, although there is a trend towards the geographical differences disappearing", ...

President Obama's 2012 budget: Nation's future depends on science, innovation

2011-02-17
WASHINGTON—February 16, 2011— Research!America's board chair, former Congressman John Edward Porter, and president, Mary Woolley, thanked President Obama for prioritizing medical, health and scientific research in his FY2012 budget proposal. The president's budget includes $31.829 billion for the National Institutes of Health ($745 million increase over 2010); $7.8 billion for the National Science Foundation ($1.2 billion increase over 2010); and $2.747 billion for the Food and Drug Administration ($382 million increase over 2010). The budget proposes $5.8 billion for ...

Finding a way to extend tomato shelf-life

2011-02-17
Tomatoes spend so much time on shelves and in refrigerators that an estimated 20 percent are lost to spoilage, according to the U.S. Department of Agriculture (USDA). But scientists with USDA's Agricultural Research Service (ARS) are working with colleagues at Purdue University to extend the shelf life of tomatoes. The research also may lead to tomatoes that taste better and are more nutritious. ARS is USDA's principal intramural scientific research agency, and the research results support the USDA priority of promoting international food security. Autar Mattoo, a ...

Running on a faster track

2011-02-17
What matters for commuters is not just if the train will be on time, but how long the journey will take. It's an important factor in public transportation and can make the difference in helping commuters choose mass transit over more polluting and costly transport like cars or airplanes. Dr. Tal Raviv and his graduate student Mor Kaspi of Tel Aviv University's Department of Industrial Engineering in the Iby and Aladar Fleischman Faculty of Engineering have developed a tool that makes passenger train journeys shorter, especially when transfers are involved — a computer-based ...

LAST 30 PRESS RELEASES:

Urgent policy actions needed to address real AI threats, scientist reveals

FOR IMMEDIATE RELEASE: Mount Sinai experts present research at SLEEP 2025

Medigap protection and plan switching among Medicare advantage enrollees with cancer

Bubbles are key to new surface coating method for lightweight magnesium alloys

Carbon stable isotope values yield different dietary associations with added sugars in children compared to adults

Scientists discover 230 new giant viruses that shape ocean life and health

Hurricanes create powerful changes deep in the ocean, study reveals

Genetic link found between iron deficiency and Crohn’s disease

Biologists target lifecycle of deadly parasite

nTIDE June 2025 Jobs Report: Employment of people with disabilities holds steady in the face of uncertainty

Throughput computing enables astronomers to use AI to decode iconic black holes

Why some kids respond better to myopia lenses? Genes might hold the answer

Kelp forest collapse alters food web and energy dynamics in the Gulf of Maine

Improving T cell responses to vaccines

Nurses speak out: fixing care for disadvantaged patients

Fecal transplants: Promising treatment or potential health risk?

US workers’ self-reported mental health outcomes by industry and occupation

Support for care economy policies by political affiliation and caregiving responsibilities

Mailed self-collection HPV tests boost cervical cancer screening rates

AMS announces 1,000 broadcast meteorologists certified

Many Americans unaware high blood pressure usually has no noticeable symptoms

IEEE study describes polymer waveguides for reliable, high-capacity optical communication

Motor protein myosin XI is crucial for active boron uptake in plants

Ultra-selective aptamers give viruses a taste of their own medicine

How the brain distinguishes between ambiguous hypotheses

New AI reimagines infectious disease forecasting

Scientific community urges greater action against the silent rise of liver diseases

Tiny but mighty: sophisticated next-gen transistors hold great promise

World's first practical surface-emitting laser for optical fiber communications developed: advancing miniaturization, energy efficiency, and cost reduction of light sources

Statins may reduce risk of death by 39% for patients with life-threatening sepsis

[Press-News.org] Xenacoelomorpha -- a new phylum in the animal kingdom