Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Fishing for the Origins of Genome Complexity

19.12.2005


Studying fish, like this ocean sulfish, scientists are revealing the link between evolution and a species’ genome. (Photo courtesy: Earthwindow.com/Mike Johnson)


Deciphering a paradox of evolution

Biologists at Georgia Tech have provided scientific support for a controversial hypothesis that has divided the fields of evolutionary genomics and evolutionary developmental biology, popularly known as evo devo, for two years. Appearing in the December 2005 issue of Trends in Genetics, researchers find that the size and complexity of a species’ genome is not an evolutionary adaptation per se, but can result as simply a consequence of a reduction in a species’ effective population size.

“As a general rule, more complex organisms, like humans, have larger genomes than less complex ones,” said J. Todd Streelman, assistant professor in the School of Biology at the Georgia Institute of Technology and co-author of the study. “You might think this means that animals with the largest genomes are the most complex – and for the most part that would be right. But it’s not always true. There are some species of frogs and some amoeba that have much larger genomes than humans.”



To help explain this paradox, a pair of scientists from Indiana University and the University of Oregon published a hotly-contested hypothesis in 2003. It said that most of the mutations that arise in organisms are not advantageous and that the smaller a species effective population size (the number of individuals who contribute genes to the next generation), the larger the genome will be.

“We agreed with some of the criticisms of the hypothesis – that one had to remove the effects of confounding factors like body size and developmental rate,” said Streelman. “We were able to remove the effects of these confounding factors and test whether genome size is adaptive.”

Their test consisted of analyzing data from 1,043 species of fresh and saltwater ray-finned fish. Previous data on genetic variability had established that freshwater species have a smaller effective population size than their marine counterparts. If the hypothesis was correct, the genome size of these freshwater fish would be larger than that of the saltwater dwellers. It was.

Then they matched the data with estimates of heterozygosity, a measure of the genetic variation of a population. Again they found that species with a smaller effective population had larger genomes.

“We see a very strong negative linear relationship between genome size and the effective population size,” said Soojin Yi, assistant professor in the School of Biology and lead author of the study. “This observation tells us that the mutations that increase the genome tend to be slightly deleterious, because population genetic theories predict such a relationship.”

“The interesting thing here is that biological complexity may passively evolve,” said Yi. “We show that at the origins, it’s not adaptive mutations, but slightly bad ones that make the genome larger. But if you have a large genome, there is more genetic material to play with to make something useful. At first, maybe these mutations aren’t so good for your genome, but as they accumulate and conditions change through evolution, they could become more complex and more beneficial.”

David Terraso | EurekAlert!
Further information:
http://www.icpa.gatech.edu

More articles from Life Sciences:

nachricht Complementing conventional antibiotics
24.05.2018 | Goethe-Universität Frankfurt am Main

nachricht Building a brain, cell by cell: Researchers make a mini neuron network (of two)
23.05.2018 | Institute of Industrial Science, The University of Tokyo

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

When corals eat plastics

24.05.2018 | Ecology, The Environment and Conservation

Surgery involving ultrasound energy found to treat high blood pressure

24.05.2018 | Medical Engineering

First chip-scale broadband optical system that can sense molecules in the mid-IR

24.05.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>