XI'AN, April 15 (Xinhua) -- Chinese scientists have sequenced the genome of the crested ibis, an achievement which may aid efforts to protect the endangered bird, researchers said Friday at a press conference in Xi'an, capital of the northwestern Shaanxi Province.
By understanding the genetic make-up of the crested ibis, researchers may be able to explain the species' low birth rate and high mortality rate, said Li Shengbin, a scientist with Xi'an Jiaotong University.
Researchers from the university and the Beijing Genomics Institute (BGI) in Shenzhen, China's flagship genome center, sequenced DNA that was separated from 1.5 ml of blood taken from a two-year-old bird.
They found that the crested ibis genome contains about 1.37 billion base pairs, about half of what is found in the human genome.
The researchers have also compared the crested ibis genome with that of the egret, a bird that lives in the same habitat but is far more fertile, said Li.
"The whole process is complicated, and we need to establish the complete nucleotide sequence of the genome," he said. "It was like making a sweater out of a messy pile of wool."
Wang Jian, the President of BGI, said the sequencing was precise and up to international standards. "The map is a basis for further genome research that will ultimately decode the mysteries of the low fertility rate of crested ibises."
He said researchers would collect DNA samples from more crested ibises for genetic and evolutionary studies before coming to any conclusion.
The DNA mapping of the crested ibis is part of the BGI's 1000 plant and animal reference genome project launched in January 2010 that has also sequenced genomes of rare species like the giant panda and Tibetan antelope.
By 2012, BGI hopes to establish one of the world's most comprehensive genome databases.
The crested ibis is the fourth bird genome to be sequenced after the chicken, zebra finch and turkey.
The rare species is found in China, Japan, Russia and the Democratic People's Republic of Korea. It is considered a symbol of good luck in China.
Environmental deterioration caused its population to rapidly shrink in the 1930s and 1940s. By the late 1950s, the bird was believed to be extinct.
In 1981, Chinese scientists found seven ibises in Shaanxi's Yangxian County, igniting hope that the species could be saved. The birds were immediately put under protection.
As of last year, China's crested ibis population had reached 1,617, including 997 in the wild and 620 raised in captivity, the State Forestry Administration said.
Including the much smaller crested ibis populations found in Japan and the Republic of Korea, the forestry administration estimates that there are around 1,814 of the rare birds in the world.
The world's first human genome sequence map was finished in June 2000. From 2000 to 2009, scientists across the world have drawn whole genome sequence maps for 1,100 species, averaging 118 a year.
Chinese scientists have completed genome sequencing for rice, domesticated silkworms, chickens, oysters as well as endangered animals like the giant panda and Tibetan antelope.