Navigation Links
Stealing life's building blocks
Date:6/8/2012

In a finding that could fundamentally re-write science's understanding of how some parasite-host relationships work, Harvard researchers have found that, despite being separated by more than 100 million years of evolution, the parasitic "corpse flower" found in southeast Asian rainforests appears to share large parts of its genome with its host vines, members of the grapevine family.

The two plants share parts of their genome, researchers believe, through a process known as "horizontal gene transfer". As opposed to vertical transfer, in which a parent passes genes to their offspring, horizontal transfer occurs when genes are passed between organisms without sexual reproduction.

As described in the June 6 issue of BMC Genomics in a study that was co-lead with Stony Brook University, researchers found that this type of genetic sharing between these two plants is much more widespread than first suspected, and that some genes borrowed by the flowers are likely functional, and had perhaps replaced vertically inherited copies. The surprising finding, Charles Davis, Professor of Organismic and Evolutionary Biology and Curator of Vascular Plants in the Harvard University Herbaria, said, suggests that the process may convey some evolutionary advantage to the flowers, which are the largest flowers in the world.

"We found that several dozen actively transcribed genes likely originated from the flower's host," said Zhenxiang Xi, a graduate student in Davis' lab, and first author of the paper. "In addition, we found evidence that about one third of the parasites own vertically inherited genes have evolved to be more like those of hosts, suggesting that there might be a fitness benefit to maintaining genes that are more host-like."

"At the outset, we wondered if it could be that a subset of these genes might provide some defense from the host mounting an attack," Davis added. "However, the genes coming to the flowers represent a broad swath of functions, including respiration, metabolism and perhaps some useful for defense. If so, these findings might reflect a sort of genomic camouflage, or genomic mimicry for the parasite."

The new paper builds on research Davis conducted in 2004, just before coming to Harvard, which focused on understanding the evolutionary origins of such "extremeophiles."

"For years, these plants have been something of an evolutionary mystery, because they simply don't possess the genetic toolkit primarily the genes associated with photosynthesis - that evolutionary biologists have used to place them on the broader tree of life," Davis said. "These plants have reduced themselves so much, they've actually lost many of the genes associated with photosynthesis."

Using newly developed genomic tools, he identified the plants that are the closest relatives of the enormous flowers, but also stumbled into something surprising - a single region in the flower's genetic code that was more like its host than itself.

The realization that the flowers and vines appeared to be related, Davis said, was a "eureka moment."

"These species are quite evolutionarily diverged from one another, yet they have a very close, intimate physical proximity," he said. "The parasite literally cannot live without being inside the host. Our study was one of the first to show that parasitic systems characterized by close physical contact are an area where horizontal gene transfer is taking place."

Knowing that horizontal gene transfer was happening, however, was only part of the story. Left unanswered, he said, were questions about the magnitude of these transfers, what type of genes were moving, whether those genes were functional in the flowers, and to what extent vertically inherited genes may have been replaced by horizontally acquired ones.

"Following the 2004 study, there was a great deal of momentum behind the idea that the parasite-host relationship was a hotbed of activity for horizontal gene transfer," Davis said. "But no one had tackled this question in a broad systematic way. Our paper was the first to hit this problem, and what we found was is gene transfer is indeed prevalent in these parasites, and that some of those genes are likely functional."

Davis' research didn't stop at the genes the flowers adopted from their host. In examining the vertically inherited genes of the parasite that is, those inherited from a parent they found that the molecular coding between the parasites were strikingly similar to those of its host. Put simply, he said, the flowers are "learning to speak the genetic language" of their hosts, and not simply acquiring their genes.

"What we think is that the genes in the parasite are independently converging on the genetic coding of the host," he said. "Of course, in this case it's more likely easier to acquire genes through horizontal gene transfer if your own genetic machinery is more like your host, but when we started to find these patterns, it amazed me. If true, it's a pretty diabolical strategy on the part of the parasite."


'/>"/>

Contact: Peter Reuell
preuell@fas.harvard.edu
617-496-8070
Harvard University
Source:Eurekalert

Related biology news :

1. Unique adaptations to a symbiotic lifestyle reveal novel targets for aphid insecticides
2. Building the European Unions Natura 2000 -- the largest ever network of protected areas
3. New study finds a protein combination is best to consume post-workout for building muscle
4. Light weights are just as good for building muscle, getting stronger, researchers find
5. CUNY Energy Institute battery system could reduce buildings electric bills
6. A cells first steps: Building a model to explain how cells grow
7. The Japanese traditional therapy, honokiol, blocks key protein in inflammatory brain damage
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/11/2017)... 11, 2017 NXT-ID, Inc. (NASDAQ:   ... announces the appointment of independent Directors Mr. Robin D. ... Board of Directors, furthering the company,s corporate governance and expertise. ... Gino Pereira , ... forward to their guidance and benefiting from their considerable expertise ...
(Date:4/5/2017)... , April 4, 2017 KEY FINDINGS ... to expand at a CAGR of 25.76% during the ... is the primary factor for the growth of the ... https://www.reportbuyer.com/product/4807905/ MARKET INSIGHTS The global stem ... technology, application, and geography. The stem cell market of ...
(Date:3/30/2017)... HONG KONG , March 30, 2017 ... developed a system for three-dimensional (3D) fingerprint identification by adopting ground ... technology into a new realm of speed and accuracy for use ... applications at an affordable cost. ... ...
Breaking Biology News(10 mins):
(Date:5/23/2017)... ... May 23, 2017 , ... Genedata, a leading provider of ... occasion with a strong presence at Bio-IT World Conference & Expo 2017 in ... invitation to all attendees to view posters on the entire range of ...
(Date:5/23/2017)... ... May 23, 2017 , ... Kathy Goin is joining ... Operations. She brings years of expertise in establishing and leading clinical operations at ... a licensed occupational therapist, through a variety of leadership roles in Clinical Operations, ...
(Date:5/22/2017)... ... May 22, 2017 , ... Baltimore biotech firm, PathSensors, ... Biohealth community in developing and issuing recommendations to grow Maryland's biohealth industry and ... by 2023. , The recommendations are contained in a report ...
(Date:5/19/2017)... ... May 19, 2017 , ... ... Program. Academic researchers with technologies ripe for commercialization, and who are affiliated ... Delaware, are encouraged to submit proposals. QED, now in its tenth round, is ...
Breaking Biology Technology: