Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Genomic comparison of ocean microbes reveals East-West divide in populations

12.10.2010
Much as an anthropologist can study populations of people to learn about their physical attributes, their environs and social structures, some marine microbiologists read the genome of microbes to glean information about the microbes themselves, their environments and lifestyles.

Using a relatively new methodology called comparative population genomics, these scientists compare the entire genomes of different populations of the same microbe to see which genes are "housekeeping" or core genes essential to all populations and which are population-specific.

Scientists are able to read a genome and translate the genes into proteins that serve particular functions. Population-specific genes sometimes tell a very clear story about the environment, for instance temperature and the availability of light and particular elements, and over time, they can point to the microbes' evolutionary adaptation to changes in the ecosystem.

Occasionally, as was the case with recent research at MIT, the population-specific genes reveal this information with crystal clarity, even providing unmistakable clues about lifestyle.

Professor Sallie (Penny) W. Chisholm of MIT's Department of Civil and Environmental Engineering (CEE) and former doctoral student Maureen Coleman compared the genetic makeup of two populations of the same oceanic photosynthetic bacterium, Prochlorococcus, one living in the Atlantic Ocean and one in the Pacific.

They found that although a continent separates the populations, they differ significantly in only one respect: those in the Atlantic have many more genes specifically related to the scavenging of phosphorus, an essential element for these microbes. And just as the variations in the beaks of Darwin's finches were evolutionary adaptations related to food availability, so too are the variations in the Prochlorococcus genes related to phosphorous gathering. Both are examples of a powerful evolutionary force at work.

"We expected to see some difference in the genes related to phosphorous, because the Atlantic Ocean has an order of magnitude lower concentration of phosphorus than the Pacific, so Atlantic populations of Prochlorococcus carry many more genes involved in extracting phosphorus from the seawater. They need more creative ways of gathering it. But we didn't expect it to be the only difference," said Chisholm. "This indicates that phosphorus availability is the dominant selective force in defining these populations."

The researchers also noted that the microbes in the Atlantic Ocean had increased numbers of phosphorous-related genes that helped them neutralize arsenic, an element they sometimes take up by mistake when they're scavenging for phosphorous. This finding "buttresses the assertion" that this is the result of a strong selective process, Chisholm said.

"We're really diagnosing the ecosystem using a specific species of microbe as a reporter," said Chisholm. "We're letting the cells tell us what they have to deal with in their environment."

She and Coleman also compared the genomes of two populations of a neighboring bacterium, Pelagibacter, and found that genes related to phosphorus gathering in that bacterium appear in far greater numbers in the Atlantic Ocean population, but with a twist. These microbes have a somewhat different repertoire of phosphorus-related genes, suggesting subtle differences between these two microbial groups with respect to how they scavenge phosphorus. This could reflect an adaptive behavior known as "niche partitioning," which allows cells sharing a microenvironment to apportion resources according to a cell's "lifestyle" rather than all competing for the same element or same form of that element.

To obtain these findings, which will appear in the online Early Edition of the Proceedings of the National Academy of Sciences the week of Oct. 11, the two scientists used the complete genomes of 13 strains of lab-cultured Prochlorococcus and Pelagibacter as reference genes, and compared these with the genes of well-documented wild microbe populations gathered at long-term oceanographic study stations near Bermuda (BATS) and Hawaii (HOTS). The work was funded by the Gordon and Betty Moore Foundation, the National Science Foundation and the U.S. Department of Energy.

The next step in this research is to make similar studies at different depths and locations to study the effects of temperature and chemical gradients on the genomes of microbial populations.

"How fast marine microbes adapt to environmental change is a big unknown," said Coleman, who is now a postdoctoral associate at Caltech. "One way to address this is to sample the population genomes over time, with parallel environmental monitoring. We might then be able to catch evolution in action. Long term study sites like HOT and BATS are crucial for this effort."

Jennifer Hirsch | EurekAlert!
Further information:
http://www.mit.edu

More articles from Life Sciences:

nachricht Fine organic particles in the atmosphere are more often solid glass beads than liquid oil droplets
21.04.2017 | Max-Planck-Institut für Chemie

nachricht Study overturns seminal research about the developing nervous system
21.04.2017 | University of California - Los Angeles Health Sciences

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

Im Focus: Quantum-physical Model System

Computer-assisted methods aid Heidelberg physicists in reproducing experiment with ultracold atoms

Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...

Im Focus: Glacier bacteria’s contribution to carbon cycling

Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.

A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

New quantum liquid crystals may play role in future of computers

21.04.2017 | Physics and Astronomy

A promising target for kidney fibrosis

21.04.2017 | Health and Medicine

Light rays from a supernova bent by the curvature of space-time around a galaxy

21.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>