The findings are reported by Mark Ungerer and colleagues at Kansas State University and appear in the October 24th issue of the journal Current Biology, published by Cell Press.
Theory predicts that for diploid species--that is, those possessing two sets of chromosomes, like most animals and plants--the origin of new species through inter-species hybridization may be facilitated by rapid reorganization of genomes. Previous work on three independently derived hybrid sunflower species has validated this mode of speciation by documenting novel structural rearrangements in their chromosomes, as well as large-scale increases in nuclear DNA content. The nuclear-genome size differences between the hybrids and their parental taxa occur in spite of the fact that all species possess the same number of chromosomes and are diploids.
In the new work, the researchers have determined that the genome size differences between the hybrid and parental sunflower species are associated with a massive proliferation of transposable genetic elements that has occurred independently in the genome of each hybrid species. Transposable elements, made famous by Barbara McClintock in her study of their behavior in maize, are related to infectious retroviruses and are capable of multiplying and inserting themselves at different points throughout a host genome. They are found in virtually all eukaryotic genomes.
The new findings not only add an interesting twist to the origin of new sunflower species through hybridization, but also suggest that the sunflower system may emerge as an excellent model group for studying the natural forces influencing the activation and proliferation of transposable elements in plants. This is because in addition to their hybrid origins, each of the three hybrid species is adapted to, and evolved in, a so-called abiotically extreme environment--two of the species are found in desert environments, while the third is adapted to salt marshes. Both hybridization and abiotic stress have been implicated as natural agents of activation and proliferation of transposable elements.
Seeing on the Quick: New Insights into Active Vision in the Brain
15.08.2018 | Eberhard Karls Universität Tübingen
New Approach to Treating Chronic Itch
15.08.2018 | Universität Zürich
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur
What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...
08.08.2018 | Event News
27.07.2018 | Event News
25.07.2018 | Event News
15.08.2018 | Physics and Astronomy
15.08.2018 | Earth Sciences
15.08.2018 | Physics and Astronomy