Navigation Links
This week in Molecular Biology and Evolution

Throughout the evolution of life on earth, bits of genetic material are routinely swapped among different species of bacteria to give them a competitive advantage. But rarely do such gene transfers happen between bacteria and higher organisms.

Now, Prof. Nikolas Nikolaidis, et. al., report on a rare case where plant genes called expansins, which are responsible for loosening or weakening protective cell wall, were transferred from plants to bacteria, fungi and amoeba that are known plant pathogens or live nearby in the soil.

"Our study reveals a rare phenomenon in molecular evolution where plant genes have been transferred to simpler organisms like fungi and bacteria," said Nikolaidis. "The protein products of these genes are weakening the plant cell wall allowing plants to grow. In the case of bacteria and fungi, these proteins are related with the ability of these species to colonize plant roots and their virulence as plant pathogens. Our study suggests that by using proteins acquired from their hosts bacteria and fungi have found new adaptive ways to utilize their hosts resources and maybe become more advanced pathogens."

The research team found two independent instances of such horizontal gene transfers that occurred from plants to bacteria and fungi. These events were followed by gene swapping amongst bacteria and fungi to refine their evolutionary fitness. The authors also looked at the details of the gene swapping at the molecular level, and found fused DNA segments that point to a similar gene function, binding to plant and bacteria cell walls.

The evolution of these non-plant expansins represents a unique case in which bacteria and fungi have found innovative and adaptive ways to interact with and infect plants. This evolutionary paradigm suggests that, despite their low frequency, such rare events have contributed significantly in the evolution of prokaryotic and eukaryotic species.

Can evolutionary tools reliably tell us about dengue virus' past outbreaks?

The mosquito-borne virus dengue is most prevalent in Southeastern Asia, with four common strains or "serotypes" of the virus infecting up to 10 percent of children in Vietnam annually. Dengue virus is a major challenge for evolutionary biologists because of its complex ecology and rapidly changing disease dynamics. But can evolutionary models become a reliable tool for epidemiologists studying infectious disease?

Coming up with a model to relate dengue's genealogical history, or phylodynamics, with the epidemiology, of the disease is challenging because of its complexity: seasonal infection rates, changes in mosquito population sizes, the different viral strains, urban versus rural populations densities, and the widespread movement of peoplewhere viruses can usurp geographic boundaries, are all contributing factors.

Now, David Rasmussen, et. al., have looked at dengue virus serotype 1 (DENV-1) in southern Vietnam, the most dominant strain of the virus found in southern Vietnam, for which a large number of sequence samples (237) are available along with reliable data on dengue hospitalizations. They incorporated some of these additional ecological complexities to tweak different evolutionary or "phylodynamic" models and were able to reconstruct dengue's past dynamics from genealogies that are consistent with the observed hospitalization data and also lead to new insights into the factors shaping viral family histories.

Their best-fit models accounted for population variation in urban vs. rural areas or the population dynamics of mosquitos, matching the hospital reported cases. This gave new insights for the researchers to create new and improved models that are more reliable and accurate for the complex dynamics of infectious disease.

Running hot and cold on the trail to measuring adaptation in fruit flies

How does species adaptation occur at the genomic level? With the ability to rapidly sequence whole genomes at low cost, next-generation sequencing has ushered in a new era of excitement in experimental evolutionary biology. The ability to manipulate model organisms and sequence whole genomes to pinpoint which genes are responsible for adaptation within a given population---dubbed "evolve and resequence"---now aims to fill in the gaps.

Authors Christian Schltterer et. al., used an experimental genetic workhorse, the fruit fly Drosophila melanogaster, and subjected a population to two different environments, one hot and one cold, and asked if they could quantify the genetic response in each. Wild flies were collected and expanded to a population of 1,000, grown in the hot and cold environments for at least 15 generations, and then subjected to whole genome sequencing.

Identifying a large number of variants involved in the adaptive response (called candidates), the authors provide convincing evidence that their candidates include loci with functions specific to either the hot or cold environment. Nevertheless, they also deduced that the number of candidate loci was greatly overestimated due to a lack of independence among them that was previously unrecognized. The authors outline how this problem, which severely limits the ability to reliably fine-map such sites, could be ameliorated by modifications to the design of such studies.


Contact: Joe Caspermeyer
Molecular Biology and Evolution (Oxford University Press)

Related biology technology :

1. Molecular Diagnostics in Genetic Testing - 2013 Study Analyzes the Size and Growth of the Molecular Diagnostics in Genetic Testing Market
2. Biotech Industry Executives Summit (10/8) to Advance the Supply Chain with Focus on Serialization, Strategic Sourcing, Clinical Supply and Molecular Diagnostics
3. Rising Interest in Molecular Biology Research Drives Demand for qPCR and dPCR Instrumentation, According to a Soon to be Released Report by Global Industry Analysts, Inc.
4. MRIGlobal Engages Industry Expert in Expansion of Molecular Diagnostic Division
5. Reproducing natures chemistry: Researchers alter molecular properties in a new way
6. Curemark Enters into Research Collaboration with The Molecular Sciences Institute (VTT/MSI)
7. Molecular Cytogenetics Market is Expected to Reach USD 1.97 Billion Globally in 2019: Transparency Market Research
8. Molecular Diagnostics: Technologies, Markets and Companies - 2013 Report
9. Molecular Biomarkers for Cancer Detection and Management
10. Managing Antibiotic-Resistant Bloodstream Infections with Rapid Molecular Diagnostics educational webinar hosted by Nanosphere and Xtalks
11. The Pistoia Alliance Releases HELM Biomolecular Representation Standard Open Source Tools
Post Your Comments:
(Date:11/25/2015)... 2015 The Global Genomics ... professional and in-depth study on the current state ... ) , The report ... definitions, classifications, applications and industry chain structure. The ... markets including development trends, competitive landscape analysis, and ...
(Date:11/24/2015)... 24, 2015 Halozyme Therapeutics, Inc. (NASDAQ: HALO ) ... New York on Wednesday, December 2 at 9:30 ... president and CEO, will provide a corporate overview. th ... at 1:00 p.m. ET/10:00 a.m. PT . Jim ... provide a corporate overview. --> th Annual Oppenheimer ...
(Date:11/24/2015)... 2015  Clintrax Global, Inc., a worldwide provider of clinical research ... announced that the company has set a new quarterly earnings record ... quarter growth posted for Q3 of 2014 to Q3 of 2015. ... Mexico , with the establishment of an Asia-Pacific ... United Kingdom and Mexico ...
(Date:11/24/2015)... York , November 24, 2015 ... a recent market research report released by Transparency Market ... to expand at a CAGR of 17.5% during the ... Prenatal Testing Market - Global Industry Analysis, Size, Volume, ... the global non-invasive prenatal testing market to reach a ...
Breaking Biology Technology:
(Date:10/26/2015)... Calif. , Oct. 26, 2015  Delta ID ... biometric authentication to mobile and PC devices, announced its ... smartphone, the arrows NX F-02H launched by NTT DOCOMO, ... NX F-02H is the second smartphone to include iris ... technology in ARROWS NX F-04G in May 2015, world,s ...
(Date:10/23/2015)... and GOLETA, California , ... HFES conference, BIOPAC and SensoMotoric Instruments (SMI) announce a ... eye tracking data captured during interactive real-world tasks ... and play integration of their established wearable solutions for ... to synchronize gaze behavior captured with SMI Eye ...
(Date:10/22/2015)... Calif., Oct. 22, 2015  Synaptics (NASDAQ: SYNA ), a ... its first quarter ended September 30, 2015. ... of fiscal 2016 grew 66 percent over the comparable quarter last ... fiscal 2016 was $23.8 million, or $0.62 per diluted share. ... for the first quarter of fiscal 2016 grew 39 percent over ...
Breaking Biology News(10 mins):