Photo of Twilight the horse. Researchers have sequenced the genome of this thoroughbred mare from Cornell University in Ithaca, N.Y. ((Doug Antzak, Cornell University))

A first draft of a horse's genome sequence has been completed and made publicly available, an advance that could aid our understanding of human genetics, leaders of the international Horse Genome Sequencing Project announced Wednesday.

The $18-million project to sequence the approximately 2.7 billion DNA base pairs in the genome of the domestic horse— Equus caballus — began last year, building on 10 years of previous research, the group said in a release.

Researchers obtained the DNA from a small sample of the blood of a thoroughbred mare named Twilight from Cornell University in Ithaca, N.Y.

Comparing the horse genome to the three billion DNA pairs found in the human genome will help researchers learn more about our genetic makeup, the researchers said. It will also help veterinary researchers better understand the diseases that affect equines.

Horses are just one of many animals to have their genetic sequence examined. Last month the U.S. Department of Agriculture gave a $10-million grant to the Swine Genome Sequencing Consortium to produce a map of the swine, or pig, genome.

Similar projects have sought to detail the genetic sequences behind animals such as dogs, cattle, zebra fish and goats.

Mapping the genome of an animal is just the first step before researchers can begin to understand how genes and sequences of genes function and promote characteristics in living organisms.