Blinding canine eye disease.

Blinding canine eye disease.Discovery for a blinding canine eye disease reveals an unprecedented mode of inheritance.A new gene for canine congenital eye disease has been identified. Defective RBP4 leads to vitamin A deficiency and abnormal eye development during pregnancy. The study defines a novel recessive mode of maternal inheritance, which may underlie other types of birth defects. Collaborating research groups from the University of Helsinki, UC Davis and the University of Jyväskylä describe a new genetic cause for canine congenital eye disease in Irish Soft-Coated Wheaten Terriers. The affected dogs suffer from bilateral microphthalmia i.e. very small eyes and anatomical defects, resulting in incurable blindness. Similar findings are seen in the Microphthalmia-Anophthalmia-Coloboma (MAC) spectrum of human congenital eye malformations, which are important causes of childhood blindness. RBP4 defect leads to vitamin A deficiency -- a known risk factor for eye diseases. The study demonstrates a novel recessive mode of genetic inheritance, which has not described before. The researchers discovered that the dam's genotype determines the puppy's disease risk as both the dam and puppy must be homozygous for the mutation to manifest the disease.As a part of the research, a DNA test has been developed for veterinary diagnosis and breeding purposes. DNA testing is important for breeders to avoid producing more blind dogs. The test can identify carriers and allow better breeding plans.

Blood in a Mosquito’s Belly Could Reveal How Diseases Spread.

Keven is a doctoral student at Michigan State University, and leader of the mosquito-catching team. Over the last few summers, John Keven has spent many long nights under the stars in Papua New Guinea. For 12 hours at a time, he’ll scour a giant green net set up between thatched huts, looking for resting mosquitoes every 20 minutes. When he spots one with his headlamp, he quietly approaches, extending a long rubber tube to suck the bug off the net. Then he blows it from the tube into a container for analysis—in a lab halfway around the world. The undigested blood inside the Anopheles punctulatus mosquitoes Keven collects is going to the research team at the Cleveland Clinic in Ohio, which uses DNA markers to identify what the insects feed on through the night—information that could help predict how they spread disease. The team’s recent testing, published last month in the journal PLoS Neglected Tropical Diseases, revealed that this type of mosquito feeds on a wider range of species than expected, potentially influencing the way it transmits malaria. The bugs feast on the humans in the villages, but also the pigs, dogs, mice and even marsupial species in the area. But this study is only one of a growing number of attempts to characterize mosquito behavior by analyzing the blood they suck. The recent emergence of Zika virus, entomologists say that matching the DNA fingerprint of human blood inside mosquitoes with individuals could help shed light on how these insects spread disease—and who is most vulnerable. “The extent to which mosquitoes don’t bite on everyone the same might actually be important when you think about who’s most important to vaccinate,” says Steve Stoddard, an entomologist at San Diego State University who has studied mosquito feeding behaviors. Data from this type of work could influence how researchers mathematically model the possible future spread of diseases carried by mosquitoes. In 2014, Stoddard and his colleagues analyzed the feeding behaviors of the Aedes aegypti mosquito, the species that is a prime suspect in the current spread of Zika virus. This species can carry dengue, too, and it likes to hang around inside human dwellings, making it even riskier. The scientists collected mosquitoes from inside 19 households in Iquitos, a Peruvian port city on the Amazon, along with cheek swabs to capture DNA from 275 residents. read more here http://www.wired.com/2016/04/blood-mosquitos-belly-reveal-diseases-spread/

HIV RESISTS CRISPR GENE EDITING.

A recent study shows that the HIV virus can overcome new efforts to defeat it using gene-cutting CRISPR technology and that the act of editing the virus's genome could even introduce mutations that help it resist future attacks . The method to tackle HIV using CRISPR have been popular since the rise of the technique, but recent studies have found that HIV quickly continued replicating even after being treated with the gene-cutting enzyme and that mutations introduced by the cutting process rendered new HIV cells unrecognisable to the enzyme. The research indicates that editing human genes to make HIV-resistant T cells would probably be more effective than directly editing the virus. Some researchers aim to edit genes made by the immune cells that HIV usually infects — called T helper cells — so that the virus cannot find a way in. Others take a different tack: equipping the T cells with gene-editing tools so that they can seek and destroy any HIV that infects them. When HIV infects a T cell, its genome is inserted into the cell’s DNA and hijacks its DNA-replicating machinery to churn out more copies of the virus. But a T cell equipped with a DNA-shearing enzyme called Cas9, together with customized pieces of RNA that guide the enzyme to a particular sequence in the HIV genome, could find, cut and cripple the invader’s genome. This seemed to work when a team led by virologist Chen Liang, at McGill University in Montreal, Canada, infected T cells that had been given the tools to incapacitate HIV. But two weeks later, Liang’s group saw that the T cells were pumping out copies of virus particles that had escaped the CRISPR attack. DNA sequencing revealed that the virus had developed mutations very near the sequence that CRISPR’s Cas9 enzyme had been programmed to cut. The team think that the problem can be surmounted, for instance by inactivating several essential HIV genes at once, or by using CRISPR in combination with HIV-attacking drugs. Gene-editing therapies that make T cells resistant to HIV invasion (by altering human, not viral, genes) would also be harder for the virus to overcome. A clinical trial is under way to test this approach using another gene-editing tool, zinc-finger nucleases. source;Nature news

CALVES UNDERGO GENETIC EDITING TO PREVENT GROWTH OF HORNS.

The two calves that grace a muddy pen on the UC Davis campus will never grow horns typical of their breed. Instead, they’ll always sport soft hair on the parts of their heads where hard mounds normally emerge. The calves were designed in a petri dish at a Minnesota-based genetics lab, with the goal of making them easier to pack into pens and trucks without the nuisance of their horns taking up valuable space. Their offspring may also lack horns, and generations of hornless cows could follow, potentially saving the dairy and cattle industry millions of dollars, said Alison Van Eenennaam, a geneticist at UC Davis’ College of Agriculture and Environmental Sciences who worked with the Minnesota lab Recombinetics. This first-of-a-kind result of a process called genetic editing is a test run that’s expected to deeply impact the cattle and dairy industry and the entire food supply, Van Eenennaam said. It’s also part of a flurry of research looking at how to make cattle easier to maintain, transport and turned into food. The research has raised concerns among some farmers and animal-rights activists who warn of the health and ethical risks of consuming genetically modified food, but so far, that hasn’t stopped the research drive. At UC Davis, animal geneticist Pablo Juan Ross has been trying to perfect a technique developed a decade ago but now gaining more acceptance to design cattle that produce only male offspring.“Males grow faster than females, and in beef production they are more desirable,” Ross said. Another project uses stem cells to produce a clone animal, Ross said. Genetic editing could also help design cows that are less prone to pneumonia, which would reduce their need for antibiotics.Van Eenennaam is keen on using word processing as an analogy to describe the differences between genetic editing and engineering. She likens genetic editing to changing the spelling of a word within a document and genetic engineering to pasting in a word from a completely different document.“You’re not bringing in something foreign ... like introducing a protein from a tomato into a fish, which is what is associated in genetic engineering,” she said. The two dairy calves had a precise section of DNA responsible for horn growth was knocked out and replaced with a precise section from a cow that does not produce that trait. Many cattle varieties do not grow horns, including Angus cattle. With dairy cattle – both male and female – horns are a given, and the animals are dehorned soon after they’re born.Once the cows are sexually mature, Van Eenennaam will collect semen from the bulls to inseminate horned cows – the route by which most cows are impregnated in the cattle and dairy industry. The plan is to track the calves’ growth and development and see whether the two faithfully transmit the hornless trait to their offspring.“The odds are 100 percent if Mendelian genetics holds true,” she said.She added that it’s not clear whether other, unexpected effects of editing will appear. If successful, it will allow the industry to bypass decades of breeding for polled, or hornless, cows. At the University of Missouri, researchers focus on genetically modifying pigs to remove genetic traits for maladies such as retinitis pigmentosa, hemophilia and cystic fibrosis, said Randall Prather, an animal geneticist at the school. Story credit; http://www.sacbee.com/news/local/health-and-medicine/article50822850.html