Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Decoding the genomes of duckweeds: low mutation rates contribute to low genetic diversity

26.03.2019

The low-down on a tiny plant: Researchers at the University of Münster and the Max Planck Institute for Chemical Ecology in Jena have found why the giant duckweed has a low genetic diversity despite its large population size: low mutation rates contribute to low genetic diversity. The results are relevant for future studies on the evolution of plants and will accelerate the use of duckweeds both for basic research and industrial applications. The study was published in “Nature Communications”.

Duckweeds – for many aquatic animals like ducks and snails, a treat, but for pond owners, sometimes a thorn in the side. The tiny and fast-growing plants are of great interest to researchers, and not at least because of their industrial applications – for example, to purify wastewater or generate energy.


Researchers took samples of duckweed from 68 waterbodies worldwide.

Klaus J. Appenroth


Close-up of the giant duckweed

Klaus J. Appenroth

An international research team from Münster, Jena (both Germany), Zurich (Switzerland) and Kerala (India) have recently studied the genomics of the giant duckweed. They discovered that genetic diversity, i.e. the total number of genetic characteristics that are different among individuals, is very low.

“This is remarkable given that their population size is very large – there can, for example, be millions of individuals in a single pond”, says Shuqing Xu, professor for plant evolutionary ecology at the University of Münster and lead author of the study.

To understand the reason behind this mystery, a team of plant researchers headed by Dr. Meret Huber from the Max Planck Institute for Chemical Ecology in Jena and the University of Münster measured the mutation rate of this duckweed under outdoor conditions, i.e. how many mutations accumulate per generation.

The result: low genetic diversity in this plant was accompanied by an extremely low mutation rate. “Our study emphasizes that accurate estimates of mutation rates are important for explaining patterns of genetic diversity among species”, says Meret Huber. The results are not only relevant for future studies on the evolution of plants, including many crops that have similar reproductive strategies like duckweeds, they will also accelerate the use of duckweeds both for basic research and industrial applications. The study was published in the journal “Nature Communications”.

Background:

Although mutations are the raw materials for evolutionary changes, they are often accompanied by fitness impairments. Evolutionary researchers have hypothesized that natural selection in species with large populations drives the mutation rate to as low as possible. According to this hypothesis, a species with a very large population size may under certain conditions evolve an extremely low mutation rate – which in turn can result in a very low genetic diversity. Until now, however, scientists had not been able to show this connection in eukaryotes, i.e. organisms whose cells have a nucleus. One reason for this is that mutation rates are difficult to measure experimentally.

The researchers took samples of the giant duckweed (Spirodela polyrhiza) from 68 waterbodies distributed all over the world and read the DNA sequences of their entire genomes. They found that in congruence with their geographic origin the samples fall into four genetic clusters: America, Europe, India and Southeast Asia. Based on the genome sequence information, they found that the genetic diversity of the species is among the lowest values reported in multicellular eukaryotes.

Because genetic diversity is determined by mutation rate and effective population size, the scientists then experimentally estimated the mutation rates and calculated effective population size. Since external conditions can influence the mutation rate, they performed the experiments under outdoor conditions. The result: by sequencing genomes, they found that the mutation rate in the giant duckweed was the lowest ever determined for multicellular eukaryotes. The estimated effective population size, as expected, is rather large.

The researchers suspect that the enormous population size of the giant duckweed, and therefore the large possibilities of selection in the course of evolution, has led to the reduction of mutations to a minimum. This in turn can explain the low genetic diversity. “Our study provides new insights into why and how genetic diversity differs among different species”, says Shuqing Xu.

Together with their collaborators, the scientists are currently working on analyzing genomes of even more duckweed samples and plan to carry out outdoor selection experiments. They wish to discover which other factors might have played roles in shaping the evolution of this plant.

Funding:

The study received financial support from the European Commission, the Alfred and Anneliese Sutter-Stöttner Foundation, the Centre for Adaptation to a Changing Environment at ETH Zurich, the Max Planck Society, and the University of Münster.

Wissenschaftliche Ansprechpartner:

Prof. Dr. Shuqing Xu
Westfälische Wilhelms-Universität Münster (WWU)
Institute for Evolution & Biodiversity
Tel: +49(0)251-83-21090
shuqing.xu@uni-muenster.de

Dr. Meret Huber
Westfälische Wilhelms-Universität Münster (WWU)
Institut für Biologie und Biotechnologie der Pflanzen
huberm@uni-muenster.de

Originalpublikation:

S. Xu et al. (2019): Low genetic variation is associated with low mutation rate in the giant duckweed. Nature Communications; DOI: 10.1038/s41467-019-09235-5

Svenja Ronge | idw - Informationsdienst Wissenschaft
Further information:
https://www.uni-muenster.de/

More articles from Life Sciences:

nachricht Chip-based optical sensor detects cancer biomarker in urine
06.12.2019 | The Optical Society

nachricht Scientist identify new marker for insecticide resistance in malaria mosquitoes
06.12.2019 | Liverpool School of Tropical Medicine

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Developing a digital twin

University of Texas and MIT researchers create virtual UAVs that can predict vehicle health, enable autonomous decision-making

In the not too distant future, we can expect to see our skies filled with unmanned aerial vehicles (UAVs) delivering packages, maybe even people, from location...

Im Focus: The coldest reaction

With ultracold chemistry, researchers get a first look at exactly what happens during a chemical reaction

The coldest chemical reaction in the known universe took place in what appears to be a chaotic mess of lasers. The appearance deceives: Deep within that...

Im Focus: How do scars form? Fascia function as a repository of mobile scar tissue

Abnormal scarring is a serious threat resulting in non-healing chronic wounds or fibrosis. Scars form when fibroblasts, a type of cell of connective tissue, reach wounded skin and deposit plugs of extracellular matrix. Until today, the question about the exact anatomical origin of these fibroblasts has not been answered. In order to find potential ways of influencing the scarring process, the team of Dr. Yuval Rinkevich, Group Leader for Regenerative Biology at the Institute of Lung Biology and Disease at Helmholtz Zentrum München, aimed to finally find an answer. As it was already known that all scars derive from a fibroblast lineage expressing the Engrailed-1 gene - a lineage not only present in skin, but also in fascia - the researchers intentionally tried to understand whether or not fascia might be the origin of fibroblasts.

Fibroblasts kit - ready to heal wounds

Im Focus: McMaster researcher warns plastic pollution in Great Lakes growing concern to ecosystem

Research from a leading international expert on the health of the Great Lakes suggests that the growing intensity and scale of pollution from plastics poses serious risks to human health and will continue to have profound consequences on the ecosystem.

In an article published this month in the Journal of Waste Resources and Recycling, Gail Krantzberg, a professor in the Booth School of Engineering Practice...

Im Focus: Machine learning microscope adapts lighting to improve diagnosis

Prototype microscope teaches itself the best illumination settings for diagnosing malaria

Engineers at Duke University have developed a microscope that adapts its lighting angles, colors and patterns while teaching itself the optimal...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

The Future of Work

03.12.2019 | Event News

First International Conference on Agrophotovoltaics in August 2020

15.11.2019 | Event News

Laser Symposium on Electromobility in Aachen: trends for the mobility revolution

15.11.2019 | Event News

 
Latest News

Solving the mystery of carbon on ocean floor

06.12.2019 | Earth Sciences

Chip-based optical sensor detects cancer biomarker in urine

06.12.2019 | Life Sciences

A platform for stable quantum computing, a playground for exotic physics

06.12.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>