Corporate Banner
Satellite Banner
Genomics
Scientific Community
 
Become a Member | Sign in
Home>News>This Article
  News
Return

With New Study, Aquatic Comb Jelly Floats into New Evolutionary Position

Published: Monday, December 16, 2013
Last Updated: Monday, December 16, 2013
Bookmark and Share
Study calls for a shift in understanding of how complex cell types evolved.

In a study that compares the genomes of aquatic life forms, researchers have found evidence to shuffle the branches of the tree of life. For more than a century, scientists thought that complex cell types, like neurons and muscles, evolved only once, after simple animals that lack these cell types branched from the rest of animals on the evolutionary tree.

A team of researchers from the National Human Genome Research Institute (NHGRI), part of the National Institutes of Health, has provided new evidence from the genomic study of a ctenophore species - a comb jelly - that challenges this long-held view.

The cornerstone of the study, published in the Dec. 13, 2013, advance online issue of Science, is the researchers' sequencing, assembly, annotation and analysis of the genome of Mnemiopsis leidyi, a comb jelly native to the coastal waters of the western Atlantic Ocean.

Whole-genome sequencing data shows that comb jellies branched from the rest of the animals before the sponge, a simple animal without complex cell types, according to the study. The results also show that critical cell types, such as neurons and muscle cells, were either lost multiple times during evolution or evolved independently in the ctenophores.

For the past 30 years, researchers have used whole-genome sequencing of organisms to advance their understanding of evolution. They do this by comparing the order of the chemical bases of DNA-150 million base pairs for comb jellies versus 3 billion in humans - that comprise the organism's genome.

While whole - genome sequencing data have been available for four of the five major animal lineages - sponges (Porifera), flat invertebrates (Placozoa), jellyfish (Cnidaria), and animals with left-right symmetry, including humans (Bilateria) - Ctenophora remained the last major animal lineage for which there were no sequenced genomes.

"Having genomic data from the ctenophores is crucial from a comparative genomics perspective, since it allows us to determine what physical and structural features were present in animals early on," said Andy Baxevanis, Ph.D., senior author of the study and senior scientist in NHGRI's Division of Intramural Research. "These data also provide us an invaluable window for determining the order of events that led to the incredible diversity that we see in the animal kingdom."

Comb jellies possess muscle cells, but the analysis of the Mnemiopsis genome showed that comb jellies lack the vast majority of genes that specify muscle types in most other animals. According to the researchers, the absence of such a large number of muscle genes suggests that muscle cells evolved independently in comb jellies, after they diverged from the rest of the animals. Comb jellies also possess a simple form of nervous system, called a nerve net, and their genome contains many of the genes involved in the nervous system. Sponges also have these genes, suggesting that they may have had the capacity to support a nervous system and perhaps lost it.

The results of the study lead to a new way of thinking about early animal evolution. "Our analysis of the Mnemiopsis genome thoroughly corroborates previous studies suggesting that ctenophores might be the sister group to the rest of the animals," said Joseph Ryan, Ph.D., lead author and a former postdoctoral research fellow in NHGRI's Genome Technology Branch, now at the Sars International Center for Marine Molecular Biology, University of Bergen, Norway. "With our whole-genome sequencing data in hand, it is now clear that the cell types that make up muscles and nervous systems were either lost in some animal lineages or that, despite the complexity of these cells, they very well may have evolved multiple times."

"Expanding our understanding of genomes across the animal kingdom is important for gaining an understanding of evolutionary adaptation at the molecular, cellular and organismal levels," said Daniel Kastner, M.D., Ph.D., NHGRI scientific director. "The whole-genome sequence of the comb jelly provides a nontraditional model through which new insights about genes and their functions, including those in our own genome, may become better understood."

The study involved collaborators from the Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, Fl.; Brown University, Providence, R.I.; the Monterey Bay Aquarium Research Institute, Moss Landing, Calif.; Rice University, Houston; the University of Michigan, Ann Arbor; and the NIH Intramural Sequencing Center (NISC), Rockville, Md.

"Our study demonstrates the power of comparative genomics research having an evolutionary point of view, probing the interface of genomics and developmental biology," said co-author Jim Mullikin, Ph.D., NISC director. "The data generated in the course of this study also provide a strong foundation for future work that will undoubtedly lead to novel findings related to the nature of animal biology."

"Over the longer term, basic biological discoveries made in organisms such as Mnemiopsis could very well lay the groundwork for translational studies focused on specific human diseases," said Dr. Baxevanis.

The genomic data and associated annotations generated in the course of this study are available on the Mnemiopsis Genome Project Portal, at (http://research.nhgri.nih.gov/mnemiopsis).


Further Information

Join For Free

Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 3,100+ scientific posters on ePosters
  • More than 4,500+ scientific videos on LabTube
  • 35 community eNewsletters


Sign In



Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into TechnologyNetworks.com you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

Drug Might Help Treat Sepsis
A DNA enzyme called Top1 plays a key role in turning on genes that cause inflammation in mouse and human cells in response to pathogens. A drug blocking this enzyme rescued mice from lethal inflammatory responses, suggesting a potential treatment for sepsis.
Wednesday, May 18, 2016
NIH Funds New Studies on Ethical, Legal and Social Impact of Genomic Information
Four new grants from the National Institutes of Health will support research on the ethical, legal and social questions raised by advances in genomics research and the increasing availability of genomic information.
Wednesday, May 18, 2016
Researchers Identify Genetic Links to Educational Attainment
Researchers at NIH have suggested that the large genetics analyses may be able to help discover biological pathways as well.
Thursday, May 12, 2016
Submissions Open for the Cancer Moonshot Program
NCI opens online platform to submit ideas about research for Cancer Moonshot.
Tuesday, April 19, 2016
NIH Sequences Genome of a Fungus
Researchers at the Institute have sequenced genome of human, mouse and rat Pneumocystis that cause life-threatening Pneumonia in immunosuppressed hosts.
Tuesday, April 12, 2016
Decoding Ties Between Vascular Disease, Alzheimer’s
NIH consortium uses big data, team science to uncover complex interplay of factors.
Tuesday, March 15, 2016
Researchers Find Link Between Death of Tumor-Support Cells and Cancer Metastasis
Researchers at NIH have found that the lifespan of supportive cells in a tumor may control the spread of cancer.
Tuesday, February 23, 2016
Tick Genome Reveals Secrets of a Successful Bloodsucker
NIH-funded study could lead to new tick control methods.
Tuesday, February 09, 2016
Genomic Signature Shared by Five Types of Cancer
National Institutes of Health researchers have identified a striking signature in tumor DNA that occurs in five different types of cancer.
Monday, February 08, 2016
Cancer Drug Target Visualized at Atomic Resolution
New study using cryo-electron microscopy shows how potential drugs could inhibit cancer.
Thursday, February 04, 2016
Genome-Wide Study Yields Markers of Lithium Response
An international consortium of scientists has identified a stretch of chromosome that is associated with responsiveness to the mood-stabilizing medication lithium among patients with bipolar disorder.
Monday, February 01, 2016
Schizophrenia’s Strongest Known Genetic Risk Deconstructed
Suspect gene may trigger runaway synaptic pruning during adolescence – NIH-funded study.
Thursday, January 28, 2016
NIH Genome Sequencing Program Targets the Genomic Bases of Common, Rare Disease
The National Institutes of Health will fund a set of genome sequencing and analysis centers whose research will focus on understanding the genomic bases of common and rare human diseases.
Friday, January 15, 2016
Three Glaucoma-Related Genes Discovered
NIH-funded genetics analysis of glaucoma is largest to date.
Tuesday, January 12, 2016
International Study Reveals New Genetic Clues to AMD
NIH-funded research provides framework for future studies of AMD biology, therapy.
Tuesday, December 22, 2015
Scientific News
Poverty Marks a Gene, Predicting Depression
New study of high-risk teens reveals a biological pathway for depression.
World’s Largest Coral Gene Database
‘Genetic toolkit’ will help shed light on which species survive climate change.
Early Genetic Changes in Premalignant Colorectal Tissue Identified
Findings point to drivers of early cancer development, targets for cancer prevention therapies.
Scientists Find Evidence That Cancer Can Arise Changes
Researchers at Rockefeller University have found a mutation that affects the proteins that package DNA without changing the DNA itself can cause a rare form of cancer.
Modified Microalgae Converts Sunlight into Valuable Medicine
A special type of microalgae can soon produce valuable chemicals such as cancer treatment drugs and much more just by harnessing energy from the sun.
Breakthrough Approach to Breast Cancer Treatment
Scripps scientists have designed a drug candidate that decreases growth of breast cancer cells.
Loss Of Y Chromosome Increases Risk Of Alzheimer’s
Men with blood cells that do not carry the Y chromosome are at greater risk of being diagnosed with Alzheimer’s disease. This is in addition to an increased risk of death from other causes, including many cancers. These new findings by researchers at Uppsala University could lead to a simple test to identify those at risk of developing Alzheimer’s disease.
A Guide to CRISPR Gene Activation
A comparison of synthetic gene-activating Cas9 proteins can help guide research and development of therapeutic approaches.
Gene That Lowers Heart Attack Risk Identified
Individuals with a rare twelve-letter deletion from a gene on chromosome 17 have significantly reduced non-HDL cholesterol levels and a 35% lower than average risk of heart disease.
Testing Non-Breast/Ovarian Cancer Genes
Researchers have found that expanding gene panel beyond breast/ovarian cancer genes in these patients does not add any clinical benefit. Instead, testing has produced more questions than answers.
Skyscraper Banner

SELECTBIO Market Reports
Go to LabTube
Go to eposters
 
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
3,100+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
4,500+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FOR FREE!