Scientists have demonstrated an automated system that uses artificial intelligence and cutting-edge image processing to rapidly examine large numbers of individual Caenorhabditis elegans, a species of nematode widely used in biological research. Beyond replacing existing manual examination steps using microfluidics and automated hardware, the system’s ability to detect subtle differences from worm-to-worm – without human intervention – can identify genetic mutations that might not have been detected otherwise.
By allowing thousands of worms to be examined autonomously in a fraction of the time required for conventional manual screening, the technique could change the way that high throughput genetic screening is carried out using C. elegans.
Hang Lu’s research team is studying genes that affect the formation and development of synapses in the worms, work that could have implications for understanding human brain development. The researchers use a model in which synapses of specific neurons are labeled by a fluorescent protein. Their research involves creating mutations in the genomes of thousands of worms and examining the resulting changes in the synapses. Mutant worms identified in this way are studied further to help understand what genes may have caused the changes in the synapses.
Filed under science neuroscience AI biology genetics brain mutations
17 August 2012
A WA study of an isolated population of Eastern European Gypsies known as “Bowlmakers” has unlocked clues about a serious developmental disease - congenital cerebellar ataxia.
Professor Luba Kalaydjieva and Dr Dimitar Azmanov, from The University of Western Australia, say the discovery of an important genetic mutation is likely to inspire other scientific work around the world.
The result of their research for the UWA-affiliated Western Australian Institute for Medical Research (WAIMR) was published online today in the prestigious American Journal of Human Genetics.
It involved working collaboratively with other Australian and European researchers to discover mutations within a gene which has never before been linked to this form of heredity ataxia in humans.
Ataxias are a large group of neurodegenerative disorders that affect the ability to maintain balance, and learn and maintain motor skills. While many genes have already been implicated in hereditary ataxias, understanding their molecular basis is far from complete. New knowledge will help the understanding of normal brain development and function, and the mechanisms of degeneration.
"Gypsies are a founder population," Professor Kalaydjieva said. "They are derived from a small number of ancestors and have remained relatively isolated from surrounding populations. The Bowlmakers - known for their wooden handicrafts such as bowls and spoons - were an ideal group to study because they are a younger sub-isolate, showing limited genetic diversity.
"We studied a novel form of ataxia in 3 families in this ethnic group. Clinical and brain-imaging investigations were done in Bulgaria, in collaboration with radiologists from Sir Charles Gairdner Hospital and Princess Margaret Hospital, and were followed-up by genetic studies at WAIMR and the Walter and Eliza Hall Institute (WEHI), Melbourne.
"Signs of ataxia were detected in early infancy when motor skills like crawling and rolling over did not develop. The affected individuals presented with global developmental delay, ataxia and intellectual deficit. MRI scans showed signs of degeneration of the cerebellum, which is part of the brain controlling motor and learning skills. Overall, the life expectancy is not decreased but the quality of life is severely affected.
"The parents of the affected individuals did not present with any clinical symptoms of the ataxia, suggesting recessive inheritance," Dr Azmanov said. "Our genetic studies showed unique changes in the gene encoding metabotropic glutamate receptor 1 (GRM1), which is important for the normal development of the cerbellar cortex. The mutations inherited by all affected individuals from their unaffected carrier parents dramatically altered the structure of the GRM1 receptor.”
Professor Kalaydjieva said the exact pathogenetic mechanisms leading to the clinical manifestations and cerebellar degeneration are yet to be explained and that this opens novel research avenues for the wider scientific community. ”It also remains to be seen if other ataxia patients around the world carry mutations in GRM1,” she said.
Source: The University of Western Australia
Filed under science neuroscience brain psychology ataxia genetics Bowlmakers
Differentiating neuronal cells (actin, microtubules and DNA)
Image by Dr. Torsten Wittmann (The Scripps Research Institute in La Jolla, California)
Filed under biology cellular differentiation neuron neuroscience science DNA
The human genome that researchers sequenced at the turn of the century doesn’t really exist as we know it.
The Human Genome project sequenced “the human genome” and is widely credited with setting in motion the most exciting era of fundamental new scientific discovery since Galileo. That’s remarkable, because in important ways “the human genome” that we have labeled as such doesn’t actually exist.
cosmin4000, istockphoto
Plato essentially asserted that things like chairs and dogs, which we observe in this physical world, and even concepts like virtues, are but imperfect representations or instances of some ideal that exists, but not in the material world. Such a Platonic ideal is “the human genome,” a sequence of about 3 billion nucleotides arrayed across a linear scale of position from the start of chromosome 1 to the end of the sex chromosomes. Whether it was obtained from one person or several has so far been shrouded in secrecy for bioethical reasons, but it makes no real difference. What we call the human genome sequence is really just a reference: it cannot account for all the variability that exists in the species, just like no single dog on earth, real or imagined, can fully incorporate all the variability in the characteristics of dogs.
Nor is the human genome we have a “’normal” genome. What would it mean to be “normal” for the nucleotide at position 1,234,547 on chromosome 11? All we know is that the donor(s) had no identified disease when bled for the cause, but sooner or later some disease will arise. Essentially all available whole genome sequences show potentially disease-producing variants, even including nonfunctional genes, in donors who were unaffected at the time.
Read more …
Filed under biology genetics genomics human genome neuroscience psychology science evolution
Paddlefish’s doubled genome may question theories on limb evolution
The American paddlefish — known for its bizarre, protruding snout and eggs harvested for caviar — duplicated its entire genome about 42 million years ago, according to a new study published in the journal Genome Biology and Evolution. This finding may add a new twist to the way scientists study how fins evolved into limbs since the paddlefish is often used as a proxy for a more representative ancestor shared by humans and fishes.
“We found that paddlefish have had their own genome duplication,” said Karen Crow, assistant professor of biology at San Francisco State University. “This creates extra genetic material that adds complexity to comparative studies. It may change the way we interpret studies on limb development.”
In order to study how human limbs develop, scientists compare the limb-building genes found in mice with fin-building genes found in fishes. Previous research on paddlefish has suggested that fishes possessed the genetic toolkit required to grow limbs long before the evolution of the four-limbed creatures (tetrapods) that developed into reptiles, birds, amphibians and mammals.
In the last decade, paddlefish have become a useful benchmark in evolutionary studies because their position on the evolutionary tree makes them a reasonably good proxy for the ancestor of the bony fishes that evolved into tetrapods such as humans. However, the fact that paddlefish underwent a genome duplication could complicate what its genes tell us about the fin-to-limb transition, says Crow.
Filed under science neuroscience genomics biology genetics psychology evolution
Brazilian construction worker has a lucky escape after a 1.8m-long iron bar fell from a building through his head.
A builder is recovering after an operation to remove a 1.8m-long iron bar from his head. The bar fell from the fifth floor of a building under construction, went through Eduardo Leite’s hard hat, pierced the back of his skull and exited between his eyes. Amazingly the 24-year-old survived and when he arrived at hospital he was conscious and able to tell doctors what had happened.
(Other Phineas Gage alikes)
(Source: Guardian)
Filed under brain neuroscience psychology science Phineas Gage
What is it that makes the human brain so special? Sure it’s big — but it’s far from the biggest brain around. You’ve heard that your brain contains 100 billion neurons — but where does that number really come from, and how does it stack up against other species?
Here are four of neuroscience’s biggest brain myths
Filed under science neuroscience brain psychology
