Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Complex cells likely arose from combination of bacterial and extreme-microbe genomes

09.09.2004


New ’ring of life’ points to mergers and acquisitions between cells



According to a new report, complex cells like those in the human body probably resulted from the fusion of genomes from an ancient bacterium and a simpler microbe, Archaea, best known for its ability to withstand extreme temperatures and hostile environments. The finding provides strong evidence that complex cells arose from combinations of simpler organisms in a symbiotic effort to survive. Jim Lake and Maria Rivera, at the University of California-Los Angeles (UCLA), report their finding in the Sept. 9 issue of the journal Nature.

Scientists refer to both bacteria and Archaea as "prokaryotes"--a cell type that has no distinct nucleus to contain the genetic material, DNA, and few other specialized components. More-complex cells, known as "eukaryotes," contain a well-defined nucleus as well as compartmentalized "organelles" that carry out metabolism and transport molecules throughout the cell. Yeast cells are some of the most-primitive eukaryotes, whereas the highly specialized cells of human beings and other mammals are among the most complex.


"A major unsolved question in biology has been where eukaryotes came from, where we came from," Lake said. "The answer is that we have two parents, and we now know who those parents were." Further, he added, the results provide a new picture of evolutionary pathways. "At least 2 billion years ago, ancestors of these two diverse prokaryotic groups fused their genomes to form the first eukaryote, and in the processes two different branches of the tree of life were fused to form the ring of life," Lake said.

The work is part of an effort supported by the National Science Foundation--the federal agency that supports research and education across all disciplines of science and engineering--to re-examine historical schemes for classifying Earth’s living creatures, a process that was once based on easily observable traits. Microbes, plants or animals were said to be related if they shared certain, mostly physical, characteristics. DNA technology now allows much closer scrutiny of hereditary molecules, which provides a more accurate and detailed picture of the genetic relationships between and among living things.

"New computational tools and comparative analyses will undoubtedly find instances in which the evolutionary record will need to be set straight," said James Rodman, a program officer in NSF directorate for biology, which funded the research. "This new fellowship among microbiologists, evolutionists, and computationalists will provide a much fuller picture of the relatedness of living things."

Lake and Rivera analyzed and compared the genomes of 30 microorganisms selected from the three categories (eukaryotes, bacteria and Archaea). All of the microbes contained about the same number of genes. The researchers then used the computer to produce genome combinations that reflected the most likely ancestors of modern eukaryotes. Their analysis, they say, showed that two ancient prokaryotes--one most similar to a bacterium, and one an Archaea--combined genomes out of a mutually advantageous need to survive.

That theory, known as endosymbiosis, has been a popular explanation of how eukaryotic cells acquired smaller components to carry out cellular processes. According to the report, modern eukaryotes obtained genes required to operate the cell from the bacterial side of the family, and the information-carrying genes from the Archaea side.

Further, the authors say, the work also sheds light on the "horizontal" transfer of genes--sideways from organism to organism, rather than from parent to offspring.

Leslie Fink | EurekAlert!
Further information:
http://www.nsf.gov

More articles from Life Sciences:

nachricht A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht On the way to developing a new active ingredient against chronic infections
18.08.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>