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 Repairing damaged hearts with self-healing heart cells
22.08.2017 | National University Health System

nachricht Biochemical 'fingerprints' reveal diabetes progression
22.08.2017 | Umea University

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

Cholesterol-lowering drugs may fight infectious disease

22.08.2017 | Health and Medicine

Meter-sized single-crystal graphene growth becomes possible

22.08.2017 | Materials Sciences

Repairing damaged hearts with self-healing heart cells

22.08.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>