The findings illustrate the ability of DNA sequence analysis to reveal aspects of animal population dynamics in the distant past and potentially illuminate the influence of human migrations in animal population changes. The new work, reported by a collaborative group of researchers including Michael Hofreiter of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, appears in the February 20th issue of the journal Current Biology, published by Cell Press.
To investigate the stability of ancient cave bear populations over time, the researchers obtained DNA samples from 29 cave bear teeth from three geographically close caves in the Ach Valley, near the Danube River in modern-day southern Germany. Twenty of the teeth ultimately provided useful mitochondrial DNA sequence (mitochondrial DNA is especially useful for tracking population changes). The findings indicated that while four sequence types (known as haplotypes) corresponded to bears 28,000 to 38,000 years old, a fifth DNA haplotype was found only in bears that were 28,000 years old or younger. These data suggested that what had been a stable, long-established cave bear population became disrupted around 28,000 years ago and was replaced by a new, genetically distinct cave bear group.
The timing of the disruption appears to roughly coincide with the arrival of modern humans in the Ach Valley, thought to have occurred by 32,000 years ago. The researchers suggest that human influence in the form of hunting and competition for sheltering caves may represent a plausible explanation for the disruption in the cave bear population, creating an opportunity for the infiltration by a neighboring cave bear group. The authors note that though the new bears successfully colonized the Ach Valley for a time, they endured only another 2,000 years before becoming extinct in the region.
Erin Doonan | EurekAlert!
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Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
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At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.
Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
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