A complete blueprint of the domestic horse’s genetic code has revealed remarkable similarities with humans, say scientists

A complete blueprint of the domestic horse's genetic code has revealed remarkable similarities with humans, say scientists.

Researchers hope the new gene map will increase their understanding of diseases in both humans and horses.

Horses suffer from more than 90 hereditary diseases which are similar to human disorders.

An international team of scientists analysed DNA from an adult female thoroughbred horse named Twilight.

Her genetic code, or genome, was found to have around 2.7 billion "letters" - slightly more than the domestic dog, but fewer than humans and cows.

The Horse Genome Project scientists were surprised to find that horses and humans shared unusually similar chromosomal arrangements. Chromosomes are the packages of DNA strands along which genes are located. During the course of evolution, parts of chromosomes can be reshuffled and switch position.

However, more than half of Twilight's genes appeared on chromosomes in the same order as genes on human chromosomes, a phenomenon known as "conserved synteny" between species.

Only 29% of dog genes display this similarity with humans. The research was published in the journal Science. Horses were first domesticated 4,000 to 6,000 years ago. The genome suggests that modern domestic horses are descended from a relatively large number of females, but few males.

Professor James Murray, from the University of California at Davis, who has worked on the Horse Genome Project since its inception in 1995, said: "Having access to multiple genome sequences makes it easier to understand all genomes, including our own.

"By looking at the horse genome, we can better understand human biology and human diseases."