Featured Research

from universities, journals, and other organizations

Microbes can influence evolution of their hosts

Date:
July 18, 2013
Source:
Vanderbilt University
Summary:
Contrary to current scientific understanding, it appears that our microbial companions play an important role in their hosts' evolution. A new study provides the first direct evidence that these microbes can contribute to the origin of new species by reducing the viability of hybrids produced between males and females of different species.

An illustration of the tree of life created in microbial culture.
Credit: Robert Brucker, Vanderbilt University

You are not just yourself. You are also the thousands of microbes that you carry. In fact, they represent an invisible majority that may be more you than you realize.

Related Articles


These microscopic fellow travelers are collectively called the microbiome. Realization that every species of plant and animal is accompanied by a distinctive microbiome is old news. But evidence of the impact that these microbes have on their hosts continues to grow rapidly in areas ranging from brain development to digestion to defense against infection to producing bodily odors.

Now, contrary to current scientific understanding, it also appears that our microbial companions play an important role in evolution. A new study, published online on July 18 by the journal Science, has provided direct evidence that these microbes can contribute to the origin of new species by reducing the viability of hybrids produced between males and females of different species.

This study provides the strongest evidence to date for the controversial hologenomic theory of evolution, which proposes that the object of Darwin's natural selection is not just the individual organism as he proposed, but the organism plus its associated microbial community. (The hologenome encompasses the genome of the host and the genomes of its microscopic symbiotes.)

"It was a high-risk proposition. The expectation in the field was that the origin of species is principally driven by genetic changes in the nucleus. Our study demonstrates that both the nuclear genome and the microbiome must be considered in a unified framework of speciation," said Associate Professor of Biological Sciences Seth Bordenstein who performed the study with post-doctoral fellow Robert Brucker.

They conducted their research using three species of the jewel wasp Nasonia. These tiny, match-head sized wasps parasitize blowflies and other pest flies, which make them useful for biological control.

"The wasps have a microbiome of 96 different groups of microorganisms," said Brucker. Two of the species they used (N. giraulti and N. longicornis) only diverged about 400,000 years ago so they are closely related genetically. This closeness is also reflected in their microbiomes, which are quite similar. The third species (N. vitripennis), on the other hand, diverged about a million years ago so there are greater differences in both its genome and microbiome, he explained.

The mortality of hybrid offspring from the two closely related species was relatively low, about 8 percent, while the mortality rate of hybrid offspring between either of them and N. vitripennis was quite high, better than 90 percent, the researchers established.

"The microbiomes of viable hybrids looked extremely similar to those of their parents, but the microbiomes of those that did not survive looked chaotic and totally different," Brucker reported.

The researchers showed that the incompatibilities that were killing the hybrids had a microbial basis by raising the wasps in a microbe-free environment. They were surprised to find that the germ-free hybrids survived just as well as purebred larvae. But when they gave the germ-free hybrids gut microbes from regular hybrids, their survival rate plummeted.

"Our results move the controversy of hologenomic evolution from an idea to an observed phenomenon," said Bordenstein. "The question is no longer whether the hologenome exists, but how common it is?"

This research was supported by award DEB 1046149 from the National Science Foundation's Dimensions of Biodiversity program.


Story Source:

The above story is based on materials provided by Vanderbilt University. The original article was written by David Salisbury. Note: Materials may be edited for content and length.


Journal Reference:

  1. Robert M. Brucker and Seth R. Bordenstein. The Hologenomic Basis of Speciation: Gut Bacteria Cause Hybrid Lethality in the Genus Nasonia. Science, 18 July 2013 DOI: 10.1126/science.1240659

Cite This Page:

Vanderbilt University. "Microbes can influence evolution of their hosts." ScienceDaily. ScienceDaily, 18 July 2013. <www.sciencedaily.com/releases/2013/07/130718142417.htm>.
Vanderbilt University. (2013, July 18). Microbes can influence evolution of their hosts. ScienceDaily. Retrieved October 31, 2014 from www.sciencedaily.com/releases/2013/07/130718142417.htm
Vanderbilt University. "Microbes can influence evolution of their hosts." ScienceDaily. www.sciencedaily.com/releases/2013/07/130718142417.htm (accessed October 31, 2014).

Share This



More Plants & Animals News

Friday, October 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Watch Baby Goose Survive A 400-Foot Cliff Dive

Watch Baby Goose Survive A 400-Foot Cliff Dive

Buzz60 (Oct. 31, 2014) — For its nature series Life Story, the BBC profiled the barnacle goose, whose chicks must make a daredevil 400-foot cliff dive from their nests to find food. Jen Markham has the astonishing video. Video provided by Buzz60
Powered by NewsLook.com
World's Salamanders At Risk From Flesh-Eating Fungus

World's Salamanders At Risk From Flesh-Eating Fungus

Newsy (Oct. 31, 2014) — The import of salamanders around the globe is thought to be contributing to the spread of a deadly fungus. Video provided by Newsy
Powered by NewsLook.com
Alcoholic Drinks In The E.U. Could Get Calorie Labels

Alcoholic Drinks In The E.U. Could Get Calorie Labels

Newsy (Oct. 31, 2014) — A health group in the United Kingdom has called for mandatory calorie labels on alcoholic beverages in the European Union. Video provided by Newsy
Powered by NewsLook.com
Malaria Threat in Liberia as Fight Against Ebola Rages

Malaria Threat in Liberia as Fight Against Ebola Rages

AFP (Oct. 31, 2014) — Focus on treating the Ebola epidemic in Liberia means that treatment for malaria, itself a killer, is hard to come by. MSF are now undertaking the mass distribution of antimalarials in Monrovia. Duration: 00:38 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins