Featured Research

from universities, journals, and other organizations

'Tree Of Life' Has Lost A Branch, According To Largest Genetic Comparison Of Higher Life Forms Ever

Date:
January 22, 2008
Source:
University of Oslo
Summary:
Biologists have made a startling discovery about the relationship between organisms that most people have never heard of. The Tree of Life must be re-drawn, textbooks need to be changed, and the discovery may also have significant impact on the development of medicines. The discovery has gained attention from biologists worldwide. The findings come from the largest ever genetic comparison of higher life forms on the planet.

The four new super-groups of life are Plants (green and red algae, and plants); Opisthokonts (amoebas, fungi, and all animals--including humans); Excavates (free-living organisms and parasites); and SAR (the new main group, an abbreviation of Stramenophiles, Alveolates, and Rhizaria, the names of some of its members).
Credit: Image courtesy of University of Oslo

Norwegian and Swiss biologists have made a startling discovery about the relationship between organisms that most people have never heard of. The Tree of Life must be re-drawn, textbooks need to be changed, and the discovery may also have significant impact on the development of medicines.

The discovery by Norwegian and Swiss researchers has gained attention from biologists worldwide. The findings come from the largest ever genetic comparison of higher life forms on the planet. Of 5000 genes examined, researchers identified 123 common genes from all known groups of organisms; these common genes have been studied more closely.

Lost a Branch

“The results were pretty astounding. All non-bacterial life on Earth—called eukaryotic life— can now be divided into four main groups instead of the five groups that we have been working with up to now,” says Kamran Shalchian-Tabrizi, an associate professor from the University of Oslo’s Department of Biology who has also worked with the Department of Zoology and Animal Biology and the Department of Genetic Medicine and Development, at the University of Geneva, Switzerland.

The Tree of Life (see illustration) has, through the discovery that the two formerly separated branches share a similar evolutionary history, lost one of its branches, and this will both improve and simplify quite a bit of scientific work in the future.

Important Discovery

“Kinship says a lot about shared traits. Our findings can be important in many fields, such as in the study of the development of life and in the manufacture of new medicines” says Shalchian-Tabrizi in an interview with the University of Oslo’s research magazine Apollon.

“Our knowledge of organisms and the development of medicines are often based on comparative studies across species. It is, therefore, essential that we know the relationships between the largest groups in the great diversity of eukaryotes,” he adds.

The research group has, for example, found that brown algae and silica algae, and groups of single cell organisms like the malaria parasite, marine foraminifera, and the green sun animalcule (acanthocystis turfacea) actually belong to the same group. Previously, these species were thought to be completely unrelated.

“The work that we published in the August edition of PLoS One means that the description of the Tree of Life must be revised in new textbooks,” says Professor Kjetill S. Jakobsen from the University of Oslo’s Centre for Ecological and Evolutionary Synthesis (CEES). He is also a member of the Microbial Evolution Research Group (MERG), led by Shalchian-Tabrizi, at the Department of Biology. MERG is one of 16 groups that the Faculty of Mathematics and Natural Sciences believes may have the potential to develop into new Centres of Excellence.

The New Branch

All life on Earth can be divided into two essentially different life forms—eukaryotes and prokaryotes. The eukaryotes gather their genetic material in a nucleus, while the prokaryotes (bacteria and archaea) have their genetic material floating freely in the cell. Eukaryotic organisms—such as humans—can, as a result of the new findings, be divided into the following four categories:

  • Plants (green and red algae, and plants)
  • Opisthokonts (amoebas, fungi, and all animals—including humans)
  • Excavates (free-living organisms and parasites)
  • SAR (the new main group, an abbreviation of Stramenophiles, Alveolates, and Rhizaria, the names of some of its members)

“The SAR group has to some extent been identified earlier, but we could not know if it was a correct observation because we lacked statistical data. To get that data, we first had to reconstruct the entire eukaryote tree with the help of these 123 genes. Chromalveolates and rhizaria were clearly separate groups until we published our results,” says Shalchian-Tabrizi.

“To make the picture a little less clear, one branch of chromalveolates is still in no man’s land. It may be that these also belong to SAR, but we will require additional genes and genomes to study this. We have set our sights on doing that in the course of the next few years,” he adds.

Fewer Events

“The Tree of Life tells the story of life on Earth, and our research can say something about how quickly life developed. Our discovery suggests that there were fewer big “events” than we have previously assumed in the development of higher life forms. The more we know about the branches on the Tree of Life, the more we can find out about life’s Big Bang, the beginning of life on Earth,” says Shalchian-Tabrizi.

Three billion years ago, there was only bacteria and Archaea. Eukaryotic life, which comprises all multi-celled organisms, developed in the sea—probably between 1.2 and 1.6 billion years ago. It was not before about 500 million years ago that the first creatures crept onto land.

“By digging down into the historical layers with the help of phylogenetic reconstruction, where we can find out about kinship between organisms at the genetic level and we can find answers to questions about how new traits developed. We are working, in a matter of speaking, with genetic archaeology. In this manner, we can also discover the cause of the Earth’s biological diversity,” says Jakobsen.


Story Source:

The above story is based on materials provided by University of Oslo. Note: Materials may be edited for content and length.


Cite This Page:

University of Oslo. "'Tree Of Life' Has Lost A Branch, According To Largest Genetic Comparison Of Higher Life Forms Ever." ScienceDaily. ScienceDaily, 22 January 2008. <www.sciencedaily.com/releases/2008/01/080121112642.htm>.
University of Oslo. (2008, January 22). 'Tree Of Life' Has Lost A Branch, According To Largest Genetic Comparison Of Higher Life Forms Ever. ScienceDaily. Retrieved April 24, 2014 from www.sciencedaily.com/releases/2008/01/080121112642.htm
University of Oslo. "'Tree Of Life' Has Lost A Branch, According To Largest Genetic Comparison Of Higher Life Forms Ever." ScienceDaily. www.sciencedaily.com/releases/2008/01/080121112642.htm (accessed April 24, 2014).

Share This



More Plants & Animals News

Thursday, April 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Fungus Killing Bats, Spreading in US

Deadly Fungus Killing Bats, Spreading in US

AP (Apr. 24, 2014) A disease that has killed more than six million cave-dwelling bats in the United States is on the move and wildlife biologists are worried. White Nose Syndrome, discovered in New York in 2006, has now spread to 25 states. (April 24) Video provided by AP
Powered by NewsLook.com
Blood From World's Oldest Woman Suggests Life Limit

Blood From World's Oldest Woman Suggests Life Limit

Newsy (Apr. 24, 2014) Scientists say for the extremely elderly, their stem cells might reach a state of exhaustion. This could limit one's life span. Video provided by Newsy
Powered by NewsLook.com
Raw: Kangaroo Rescued from Swimming Pool

Raw: Kangaroo Rescued from Swimming Pool

AP (Apr. 24, 2014) A kangaroo was saved from drowning in a backyard suburban swimming pool in Australia's Victoria state on Thursday. Australian broadcaster Channel 7 showed footage of the kangaroo struggling to get out of the pool. (April 24) Video provided by AP
Powered by NewsLook.com
Monkeys Are Better At Math Than We Thought, Study Shows

Monkeys Are Better At Math Than We Thought, Study Shows

Newsy (Apr. 23, 2014) A Harvard University study suggests monkeys can use symbols to perform basic math calculations. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins