Horse genome 'remarkably similar to humans'
Scientists successfully decode horse genome, showing remarkable similarities to humans
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Friday, 06, Nov 2009 10:57
By Sarah Garrod.
The genome of a domestic horse has been successfully decoded, revealing the animal shares much of the DNA of humans.
Scientists who have published their research in the journal Science say their findings mark a critical starting point for mapping disease genes in horses.
Revealed in the research are the similarities between the horse and bovid animals such as cattle and goats, as well as the more than one million genetic differences across a variety of horse breeds.
"Horses and humans suffer from similar illnesses, so identifying the genetic culprits in horses promises to deepen our knowledge of disease in both organisms," said senior author Kerstin Lindblad-Toh.
"The horse genome sequence is a key enabling resource toward this goal."
The scientists said that while horses have been used by humans for centuries, primarily as a source of transportation, they also have a common bond genetically, and like other mammals share much of the same DNA. Moreover, horses suffer from more than 90 hereditary diseases that show similarities to those in humans.
To generate a high-quality genome sequence, the researchers analysed DNA from an adult female thoroughbred named Twilight. Her DNA was sequenced using capillary DNA sequencing technology (known as Sanger sequencing) to reveal a genome that is roughly 2.7 billion "letters", or nucleotides, in size.
The researchers said: "A remarkable feature of the horse genome is the small number of chromosomal rearrangements that have occurred in horses relative to humans.
"During the course of evolution, parts of chromosomes can get shuffled to other locations in the genome, or they can remain in their original ancestral order, like beads on a string — a situation known as "synteny." More than half of the horse chromosomes show synteny with a single human chromosome. This is in contrast to dogs, where the figure is less than one-third."
In addition to sequencing the genome of a thoroughbred horse, the researchers also examined DNA from a variety of other horse breeds, including the American quarter horse, Andalusian, Arabian, Belgian draft horse, Hanoverian, Hakkaido, Icelandic horse, Norwegian fjord horse, and Standardbred breeds.