Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The world`s most stable genome has been identified in aphid endosymbionts

01.07.2002


Bacteria that reproduce inside aphids have not changed their genetic make-up for the last 50-70 million years. This makes the genomes of these bacteria the most stable of all organisms yet studied. This finding is presented by a team of scientists at Uppsala University, Sweden, in the latest issue of the scientific journal Science.



Under the leadership of Professor Siv Andersson, researchers Ivica Tama, Lisa Klasson, Björn Canbäck, Kristina Näslund, Ann-Sofie Eriksson, and Johan Sandström at the Department of Molecular Evolution, Center for Evolutionary Biology, in collaboration with Professor Nancy Moran in Tucson, Arizona, have described the entire genetic make-up of a bacterium that reproduces inside aphids, Buchnera (Sg) and compared it to that of a close relative, Buchnera (Ap).

These aphid endosymbionts, so called because they live in symbiosis with aphids, are closely related to common bacteria like Salmonella, but the adaptation to the aphids have entailed a drastic reduction in the size of the genome, which now consists of only 640,000 bases, about 14% of the genome of Salmonella species.


Aphid endosymbionts produce important amino acids that are not present in the plant sap that the aphids drink. The bacteria live in a special type of cell in the body of the aphids and are transmitted from one generation to the next by being packed into the eggs of the aphides. These bacteria are believed to have lived in symbiosis with aphids for at least 150 million years. They have now become so important that aphides can no longer live without their bacteria. If aphids treated with antibiotics, they becomes sterile -- or die.

With the aid of available fossil data from aphids, it has been estimated that the aphids that harbor these two bacteria diverged from each other roughly 50-70 million years ago. Since these aphis symbionts have lived enclosed in the bodies of the aphids, this dating can also be used to determine when the bacterial endosymbionts diverged from each other. By measuring differences in the two genomes, the Uppsala scientists have been able to calculate for the first time exactly how many mutations have taken place in the genome of a bacterium in nature over a period spanning 50-70 million years. Surprisingly, it has now been shown that these tiny, isolated aphis bacteria have largely escaped the ravages of time. The biggest surprise is that the order of the genes has not changed over the past 50 million years.

This stability is in stark contrast to the genomes of Salmonella species, which change very rapidly in structure. It has been calculated that the genomic structure of Salmonella has been altered at a rate more than 2,000 times that of the aphid endosymbionts. The secret behind the extreme stability of the aphid endosymbionts probably lies in the fact that during the early process of degradation they eliminated the genes that are needed for cutting and pasting genetic material.

However, it is extremely unlikely that the aphids` stable minibacteria will ever return to a normal life outside the aphids. They are now completely controlled by the aphids, so much so that the question can be raised whether they should be seen as bacteria or rather as organs of aphides. But if that is the case, then this is the first organ that has its own genetic code!

Jon Hogdal | alfa
Further information:
http://www.uu.se

More articles from Life Sciences:

nachricht Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

nachricht The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>