Tag Archives: Cornell University

Why huskies have blue eyes

DNA testing of more than 6,000 dogs has revealed that a duplication on canine chromosome 18 is strongly associated with blue eyes in Siberian Huskies, according to a study published October 4, 2018, in the open-access journal PLOS Genetics by Adam Boyko and Aaron Sams of Embark Veterinary, Inc., and colleagues.

Embark is a dog DNA startup company headquartered in Boston, MA, and Ithaca, NY, and research partner of the Cornell University College of Veterinary Medicine. According to the authors, this represents the first consumer genomics study ever conducted in a non-human model and the largest canine genome-wide association study to date.

Lakota

Embark dog, Lakota, shows off bright blue eyes. Credit: Jamie Leszczak CCAL

Consumer genomics enables genetic discovery on an unprecedented scale by linking very large databases of genomic data with phenotype information voluntarily submitted via web-based surveys. But the promise of consumer genomic data is not limited to human research. Genomic tools for dogs are readily available but the genetic underpinnings of many important traits remain undiscovered. Although two genetic variants are known to underlie blue eye color in some dogs, these do not explain the trait in some other dogs, like Siberian Huskies.

To address this gap in knowledge, Boyko, Sams and colleagues used a diverse panel of 6,070 genetically tested dogs with owners that contributed phenotype data via web-based surveys and photo uploads. They found that a 98.6-kilobase duplication on chromosome 18 near the ALX4 gene, which plays an important role in mammalian eye development, was strongly associated with variation in blue eye color, primarily in Siberian Huskies but also in non-merle Australian Shepherds. One copy of the variant was enough to cause blue eyes or heterochromia (blue and brown eyes), although some dogs with the variant did not have blue eyes, so other genetic or environmental factors are still involved.

Future studies of the functional mechanism underlying this association may lead to the discovery of a novel pathway by which blue eyes develop in mammals. From a broader perspective, the results underscore the power of consumer data-driven discovery in non-human species, especially dogs, where there is intense owner interest in the personal genomic information of their pets, a high level of engagement with web-based surveys, and an underlying genetic architecture ideal for mapping studies.

Aaron J. Sams adds: “Using genetic data from the pets of our customers, combined with eye colors reported by customers for those same animals, we have discovered a genetic duplication that is strongly associated with blue eye color. This study demonstrates the power of the approach that Embark is taking towards improving canine health. In a single year, we collected enough data to conduct the largest canine study of its kind. Embark is currently pursuing similar research projects in a range of morphological and health-related traits and we hope to continue to use our platform to move canine genetics and health forward in a very real way.”

Source:  Science Daily and PLOS Genetics

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First puppies born by in vitro fertilization

Researchers from Cornell University and the Smithsonian Institution have solved the decades-long puzzle of canine in vitro fertilization (IVF), resulting in the world’s first litter of IVF puppies.

Photo by Mike Carroll, Cornell University College of Veterinary Medicine

Photo by Mike Carroll, Cornell University College of Veterinary Medicine

The breakthrough, described in a study published in the journal Public Library of Science ONE, opens the door for preserving endangered canid species using assisted reproduction techniques. It could also enable researchers to eradicate heritable diseases in dogs and facilitate the study of genetic diseases in dogs and humans, which share many of the same or similar illnesses.

Researchers at the Cornell laboratory transferred 19 embryos to a host female dog, who gave birth last spring to seven healthy puppies. Genetic testing shows that two are from a beagle mother and a cocker spaniel father, and five from two pairings of beagle fathers and mothers.

“Since the mid-1970s, people have been trying to do [IVF] in a dog and have been unsuccessful,” said co-author Alex Travis, associate professor of reproductive biology at the Baker Institute for Animal Health in Cornell’s College of Veterinary Medicine.

The paper’s first author, Jennifer Nagashima, was a graduate student whose participation in the project was funded by the Smithsonian Conservation Biology Institute (SCBI) and Cornell’s Atkinson Center for a Sustainable Future. The National Institutes of Health and the Baker Institute provided funding for the project itself.

Laboratories perform successful IVF with other mammals—including humans—by retrieving mature eggs and sperm and combining them in an artificial environment to produce embryos. The embryos are transferred to a host female at the right time in her reproductive cycle.

Past attempts at canine IVF failed because a female dog’s reproductive cycle differs from that of other mammals. Canine eggs retrieved at the same stage of cell maturation as other animals failed to fertilize. By applying the oocyte biology expertise of SCBI’s Nucharin Songsasen, a research biologist and co-author, the team found that if they left the egg in the oviduct one extra day, the eggs reached the stage where fertilization was most likely to occur.

In addition, the female canine tract plays a role in preparing sperm for fertilization, so researchers had to simulate those conditions in the lab. Building on Travis’s earlier work on sperm physiology, the team found that sperm could be artificially prepared by adding magnesium to the cell culture.

“We made those two changes, and now we achieve success in fertilization rates at 80 to 90 percent,” Travis said.

The final challenge arises because female dogs can only become pregnant once or twice a year. This means embryos must be created ahead of time and preserved until the host female is at the right point in her cycle.

The birth of IVF puppies has wide implications for wildlife conservation. “We can freeze and bank sperm, and use it for artificial insemination,” Travis said. “We can also freeze oocytes, but in the absence of in vitro fertilization, we couldn’t use them. Now we can use this technique to conserve the genetics of endangered species.” The method can also be used to preserve rare breeds of show and working dogs.

In addition, embryonic dogs now offer a “powerful tool for understanding the genetic basis of diseases” in canines and humans, Travis said. Dogs share more than 350 similar heritable disorders and traits with humans, almost twice the number as any other species.

A successful IVF process for canines may one day enable researchers to remove genetic diseases and traits in an embryo, ridding dogs of heritable diseases such as lymphoma, a cancer that is more prevalent in breeds like Golden Retrievers. “With a combination of gene editing techniques and IVF, we can potentially prevent genetic disease before it starts,” Travis said.

Source:  Cornell University media release

 

More fat and less protein for sniffing dogs

Sniffing dog checking luggage. (Credit: © Monika Wisniewska / Fotolia)

A detector dog checking luggage. (Credit: © Monika Wisniewska / Fotolia)

A study  funded with a $1 million grant from the U.S. Department of Justice, has found that detection dogs are more reliable detectors than previously thought.  The study has been conducted by Cornell’s College of Veterinary Medicine.

The study is the first to be conducted in the world’s only detection dog research facility designed in conjunction with a military dog trainer. The Alabama facility, which provides expert detection dogs to police and military forces, flushes out fumes between tests, ensuring a fresh field each time.

Researchers have found that the key to improving a dogs’ smelling skills through diet is achieved by limiting proteins and increasing fats.  Such a diet, the research team says, appears to help dogs return to lower body temperatures after exercise, which reduces panting and, thereby, improves sniffing.

‘Dogs tested in the new facility signaled with 90 percent and above accuracy. We also found we can push detection performance even further with the right kind of food.’ said Joseph Wakshlag, associate professor of clinical studies and chief of nutrition at Cornell’s College of Veterinary Medicine.

During an 18-month period, the research team rotated 17 trained dogs through three diets: a high-end performance diet, regular adult dog food, and regular adult dog food diluted with corn oil. Measuring how different diets affected each dog, they found that dogs eating the normal diet enhanced with corn oil returned to normal body temperatures most quickly after exercise and were better able to detect smokeless powder, ammonia nitrate and TNT.

‘Corn oil has lots of polyunsaturated fats, similar to what you’d find in a lot of nuts and common grocery store seed oils,’ said Wakshlag. ‘Past data from elsewhere suggest that these polyunsaturated fats might enhance the sense of smell, and it looks like that may be true for detection dogs. It could be that fat somehow improves nose-signaling structures or reduces body temperature or both. But lowering protein also played a part in improving olfaction.’

‘If you’re a dog, digesting protein raises body temperature, so the longer your body temperature is up, the longer you keep panting, and the harder it is to smell well,’ said Wakshlag.

Source:  Cornell University media release

Kissing your dog and the link to gum disease

My mother was never happy when our dog got too close and  managed to lick her on the mouth.   In the Snoopy cartoons, you might remember when Lucy would run around yelling ‘Get the iodine, get the hot water.  I’ve been kissed by a dog.’ 

It turns out that there is need for caution when considering the mouth-to-mouth contact with your dog.

Researchers from Japan have tracked a microbe that is very common in dogs but rare in humans.   In dog owners, 16% of them had the microbe and it appears that they share close contact with their dogs – including kissing.

The researchers also found ten human strains of periodontitis-related bacteria in the dogs’ mouths.  And they found that low levels of contact were enough to transmit mouth bacteria either way.

In considering the research, Dr Paul Maza, of the College of Veterinary Medicine at Cornell University, told America’s Fox News:  ‘Many of the different types of bacteria in dogs and cats are the same type of bacteria as in humans. If owners practice oral hygiene on their pets, such as  brushing their teeth, a pet’s mouth can actually be even cleaner than a human mouth.’

Read the full story in the Daily Mail.