Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Peanut worms are annelids

03.03.2011
The phylum Annelida has just gained a new member / Peanut worm is no longer recognized as separate group

Recent molecular phylogenetic analysis has shown that the marine animals known as peanut worms are not a separate phylum, but are definitely part of the family of annelids, also known as segmented worms. This is a classification that seemed questionable in the past in view of the fact that peanut worms – or the Sipunculidae, to give them their scientific name – have neither segments nor bristles.


Sipunculus nudus of the group of Sipunculidae with a length of about 8 centimeters. photo/©: Dr Anja Schulze, Texas A&M University at Galveston, USA

The latter are considered typical characteristics of annelids, which include more than 16,500 identified species and to which our common earthworm belongs. "Our molecular data clearly demonstrates that there is no doubt anymore that the Sipunculidae should be classified as members of these segmented worms," explains Dr Bernhard Lieb of the Institute of Zoology at Johannes Gutenberg University Mainz (JGU). The results were obtained as part of a broad study in which the phylogenetic development and relationships within the phylum Annelida were analyzed in terms of basic molecular biology to be then re-evaluated. Participating in the project are the universities of Osnabrück, Potsdam, Mainz, and Leipzig, together with the Max Planck Institute of Molecular Genetics in Berlin. The results have now been published online in the journal Nature.

"The relationships between the various annelids with regard to both morphological and molecular biological aspects have been a matter of dispute," states Lieb. Segmented worms are the most prevalent of marine macrofauna – their habitat ranges from tidal zones to the deep oceans. Usually, they have been divided into two main classes: the Clitellata, which have few bristles, e.g. earthworms, and leeches on the one hand and the Polychaeta, literally the 'many bristled', on the other hand. The evolutionary and deep branching patterns of annelid lineage are still the subject of on-going scientific debate, although it has become increasingly clear that other groups that had previously been classified separately, such as peanut worms and beard worms, are actually members of this phylum. By means of identifying some 48,000 amino acid positions in 34 different representatives of the phylum Annelida, the research group headed by the universities of Osnabrück and Potsdam has put together the hitherto most detailed database for the family of segmented worms. This has enabled the group to re-evaluate and reconstruct the phylogenetic interrelationships and evolution of this extensive and highly diverse group of animals.

The molecular data on Sipunculus nudus – the peanut worm – gathered by the team in Mainz led by Bernhard Lieb shows that the genetic characteristics of the worm, which lives in sand and silt at the bottom of the sea, clearly indicates that it is a member of the annelid family. In evolutionary terms the peanut worm is likely to be a basal group that diverged very early during evolution. It is conjectured on the basis of the sparse fossil record that the annelids first appeared in the Cambrian Period, roughly 550-490 million years ago. "We assume that segmentation was a very early characteristic of the annelids and that the peanut worm has lost its segmentation during the course of evolution," clarifies Lieb.

Primarily, new DNA sequencing technologies, so-called next-generation sequencing (NGS), made such comprehensive genetic investigations become possible. The Illumina Hiseq2000 sequencer recently acquired by the Institute of Genetics at JGU can analyze vast amounts of data, and sequence up to 200 gigabases of DNA per run within a single week. This means that whole genomes can be sequenced in a relatively short time, opening up completely new avenues for wide-ranging research.

Petra Giegerich | idw
Further information:
http://www.uni-mainz.de/eng/14040.php
http://www.staff.uni-mainz.de/lieb/

Further reports about: Annelida DNA Genetics Peanut Sipunculidae deep ocean molecular data segmented worms

More articles from Life Sciences:

nachricht Closing in on advanced prostate cancer
13.12.2017 | Institute for Research in Biomedicine (IRB Barcelona)

nachricht Visualizing single molecules in whole cells with a new spin
13.12.2017 | Wyss Institute for Biologically Inspired Engineering at Harvard

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

A whole-body approach to understanding chemosensory cells

13.12.2017 | Health and Medicine

Water without windows: Capturing water vapor inside an electron microscope

13.12.2017 | Physics and Astronomy

Cellular Self-Digestion Process Triggers Autoimmune Disease

13.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>