That means that village dogs from most African regions are genetically distinct from non-native breeds and mixed-breed dogs. They also are more genetically diverse because they have not been subjected to strict breeding, which artificially selects genes and narrows breeds’ gene pools.
The study, published online Aug. 3 in the Proceedings of the National Academy of Sciences, sheds light on the poorly understood history of dog domestication. Future work may help explain the timing and locations of dog domestication and how dogs have adapted to the African environment, human settlements and dietary shifts.
“The genes of modern breeds all cluster together in one little group, but the African village dogs we sampled show much greater diversity genetically,” said lead author Adam Boyko, a research associate in the lab of Carlos Bustamante, the paper’s senior author and a professor of biological statistics and computational biology.
Field researchers from the University of California-Davis, who are part of the Cornell-based Village Dog Genetic Diversity Project, and others, including local veterinarians, sampled 318 village dogs from seven regions in Egypt, Uganda and Namibia. They also looked at breed dogs, including those reputed to be from Africa, Puerto Rican dogs and mixed-breed dogs from the United States.
Researchers and veterinarians also collected photos and information on weight, age, coat color and body measurements and sent blood samples for analysis to the Canine DNA Bank at the Baker Institute for Animal Health, part of Cornell’s College of Veterinary Medicine, which maintains a growing DNA archive of dogs worldwide.Boyko, Bustamante and colleagues used a computer program to track genetic diversity in the samples. They found that the African village dogs are a mosaic of indigenous dogs descended from early migrants to Africa and non-native mixed-breed dogs. Such reputed African breeds as Pharaoh hounds and
Rhodesian ridgebacks clustered with non-native dogs, suggesting they originated from outside of Africa.
A previous study of village dog genetics confirmed that domesticated dogs likely originated from Eurasian wolves some 15,000 to 40,000 years ago, and reported that East Asian village dogs had more genetic diversity than any others sampled for the study, suggesting that dogs were first domesticated in East Asia. But the African village dogs analyzed in this study revealed similar genetic diversity, which raises doubt on the claim that dogs were first domesticated in East Asia.
As the group continues to collect samples from worldwide locations, including the Americas, the researchers will explore where modern breeds originated and how much genetic diversity has been lost with the development of modern breeds.
The researchers are interested in working with dog owners and local veterinarians to get more DNA samples of dogs from remote corners of the world. For more information: http://villagedogs.canmap.org.
Co-authors included Heidi Parker and Elaine Ostrander, geneticists at the National Human Genome Research Institute; Rory Todhunter, a professor of clinical sciences in Cornell's College of Veterinary Medicine; and Paul Jones, a genetics researcher at the Waltham Centre for Pet Nutrition in the United Kingdom, among others.
The study was funded by Cornell’s Center for Vertebrate Genomics, Department of Clinical Sciences and Baker Institute of Animal Health; the National Institutes of Health; and the National Science Foundation.
The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie
Party discipline for jumping genes
22.09.2017 | Veterinärmedizinische Universität Wien
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...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
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22.09.2017 | Physics and Astronomy