BEIJING, Feb. 6 (Xinhua) -- A recent joint study has revealed the evolutionary history of crested ibis through complete genomic sequences of modern and historic population samples, offering reference for better protection of this endangered species.

Although the population of the crested ibis, once believed to be extinct in China, has been growing in recent years thanks to decades of conservation, there is limited research on its evolution history, which is key to increasing its genetic diversity and better breeding.

Previous research has focused on its population size and changes in its living environment, but they lack whole-genome data or are based only on living groups.

Scientists from the Kunming Institute of Zoology under the Chinese Academy of Sciences cooperated with scientists from Spain and Denmark and collected 57 historic crested ibis samples from nine museums around the world.

The samples date back to between the end of the 19th century and the beginning of the 20th century. The geographic origin of the samples broadly covers the historical distribution of the species, including east China, northwest China, northeast China, Japan and Russia.

They obtained the genome-wide resequencing data of the historical samples and compared it with the data of the current living population in the conservation area.

The results showed that the number of crested ibis started to decline about 10,000 years ago when temperatures rose. The modern group shows reduced diversity and has lost almost half of the genetic variations in ancestors.

The research demonstrated that the future breeding of the crested ibis should combine genetic studies to effectively avoid inbreeding and increase genetic diversity.

The research method of using genetic information of museum samples may provide an example for research on other endangered species.

The research was published in the journal Current Biology.