C

Millions of migratory(迁徙的)birds occupy seasonally favorable breeding(繁殖)grounds in the Arctic, but scientists know little about the formation, maintenance and future of the migration routes of Arctic birds and the genetic determinants of migratory distance. In a new study, a multinational team of researchers under the leadership of Dr. ZHAN Xiangjiang from the Institute of Zoology of the Chinese Academy of Sciences integrated two state-of-the-art techniques-satellite tracking and whole genome sequencing(基因排序)-and established a continental-scale migration system of peregrine falcons in Eurasian Arctic.


The researchers tracked 56 peregrine falcons from six Eurasian Arctic breeding populations and sequenced 35 genomes from four of these populations to study the migration of this species. They found that the birds used five migration routes across Eurasia, probably established between the last Ice Age 22, 000 years ago and the middle-Holocene 6, 000 years ago. "Peregrine falcons initiated their autumn migration mainly in September, and arrived at their wintering areas mainly in October, " said Professor Mike Bruford, an ecologist at Cardiff University. "Peregrine falcons that depart from different breeding grounds use different routes, and winter at widely distributed sites across four distinct regions. Individual birds that were tracked for more than one year exhibited strong path repeatability during migration, complete loyalty to wintering locations and limited breeding dispersal(扩散). "

The researchers quantified the migration strategies and found that migration distance is the most significant differentiation. They used whole genome sequencing and found a gene-ADCY8, which is known to be involved in long-term memory in other animals in previous research- associated with differences in migratory distance. They found ADCY8 had a variant at high frequency in long-distance migrant populations of peregrine falcons, indicating this variant is being favorably selected because it may increase powers of long-term memory thought to be essential for long-distance migration.

"Previous studies have identified several candidate genomic regions that may regulate migration-but our work is the strongest demonstration of a specific gene associated with migratory behavior yet identified, "Professor Bruford said. The researchers further looked at models of likely future migration behavior to predict the impact of global warming. If the climate warms at the same rate as it has in recent decades, they predict peregrine populations in western Eurasia have the highest probability of population decline and may stop migrating altogether.

"Our work is the first to begin to understand the way ecological factors may interact in migratory birds, " said Dr. ZHAN Xiangjiang. "We hope it will serve as a cornerstone to help conserve migratory species in the world. "