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Feb. 10 (UPI) -- Scientists have taken advantage of improvements in genomic sequencing technology to produce a newer, more detailed dog reference genome. The new reference genome measures 2.8 gigabases in length, which means the sequence contains 2.8 billion base pairs. Each base pair features two complementary DNA bases.
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A detailed reference genome is an important tool for geneticists, and scientists expect the new, more complete dog reference genome -- described Wednesday in the journal Communications Biology -- to aid investigations of the links between DNA and health problems in both dogs and humans.
The new reference genome was made possible by technological advances and better funding.
"We have needed a new genome assembly for quite some time, but it is [not until] now that we have been able to secure funding to generate this tool for the community," corresponding author Kerstin Lindblad-Toh, professor of comparative genomics at Uppsala University in Sweden, told UPI in an email.
The first dog reference genome was produced during the early 2000s. At the time, sequencing technology was capable of sequencing only a few hundred base pairs at a time. The sequencing process was slow-going and required large amounts of computing power.
Through the use of so-called "short-read" genomic sequencing technology, researchers were only able to produce a sparsely transcribed reference genome. The original reference genome featured lots of large gaps -- long stretches of missing DNA code.
For the new study, researchers deployed "long-read" genomic sequencing technology to reduce the number of gaps in the reference genome from 23,000 to just 585.
The new reference genome was assembled "de novo," which means scientists relied on genetic samples from a single canine, sequencing the DNA without comparing genetic text to the genomes of other dogs.
"It is like doing a jigsaw puzzle without the picture," said Lindblad-Toh. "The reference then becomes the picture to which future puzzlers can compare."
Human reference genomes are assembled using a combination of individual genomes, to protect the privacy of any one individual's genetic data.
The new reference dog genome isn't just a giant stretch of text. It's also annotated, or mapped, revealing the locations of genes, the sequences of DNA responsible for the synthesis of important proteins and other biomolecules.
The new reference genome also features information on where and in what kinds of tissue different genes are active, as well as data on how different genes are turned on and off.
"The annotated reference also includes a map of where hundreds of other dogs, including those from different breeds, are different to the reference dog genome," said Lindblad-Toh.
This kind of variation is natural. When scientists are looking for genetic changes related to disease, it's helpful for researchers to be able to rule out genetic variation among healthy individuals, while homing in on genetic differences between healthy and sick individuals.
With a more complete reference genome, scientists expect surveys of disease-related genetic variations to yield more results.
But more than just offer insights into the health problems that plague dogs, researchers hope the new reference genome will aid the study of disease-related mutations in the human genome.
"Humans and dogs are close on an evolutionary scale, closer than humans and mice," said Lindblad-Toh. "Humans and pet dogs live together, so the dogs are exposed to the same environment and often eat similar diets. Dogs also have heritable diseases which are clinically similar to human disease."
Like doctors, veterinarians keep records of a dog's medical history. Vets record how dogs are treated and how they respond to those treatments.
"Dogs at the vet and people at the doctor are often treated in very similar ways," said Lindblad-Toh. "Information we learn from studying the genetics of dog disease, and treatment response, can be lifted back into human medicine. This is more accurate now with the new genome."
