Akiyama Takuya, Momose Kunikazu, Onuma Manabu, Matsumoto Fumio, Masuda Ryuichi
1 Department of Natural History Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan.
2 Red-crowned Crane Conservancy, Kushiro 085-0036, Japan.
Zoolog Sci. 2017 Jun;34(3):211-216. doi: 10.2108/zs160194.
The red-crowned crane (Grus japonensis) is recognized internationally as an endangered species. Migratory populations breed in eastern Russia and northeastern China, whereas the resident population inhabits the island of Hokkaido, Japan. Although the population inhabiting Hokkaido had experienced a severe bottleneck by the end of the 19th century, the population size has recovered to about 1500 and continues to increase now thanks to conservation efforts. A previous study reported that no marked genetic differences were seen in the island population, and that the genetic variation of the whole population on Hokkaido was lower than that of the continental population. However, the precise genetic structure of the island population in the past or near present remains unclear. To better understand the spatiotemporal changes in the genetic structure of the island population, we performed mitochondrial DNA (mtDNA) analyses using stuffed specimens (years 1878-2001) and tissue or blood samples (years 1970-2014). We found three haplotypes in the island population, one of which was a novel mtDNA haplotype in 1997 and 2007 samples. In addition, there was no clear difference in the haplotype frequency through the time span. These results suggest that the low genetic variation of the island population persisted for the last hundred years. It is thus nearly impossible for the island population to recover its genetic variation in isolation. Conservation plans for this species should therefore include the promotion of genetic exchanges between the continental and island populations, such as through artificial introduction to Hokkaido.
丹顶鹤（Grus japonensis）在国际上被公认为濒危物种。迁徙种群在俄罗斯东部和中国东北繁殖，而留鸟种群栖息在日本北海道岛。尽管北海道的种群在19世纪末经历了严重的瓶颈，但由于保护措施，种群数量已恢复到约1500只，并且现在仍在继续增加。先前的一项研究报告称，在该岛屿种群中未发现明显的遗传差异，并且北海道整个种群的遗传变异低于大陆种群。然而，过去或近期该岛屿种群的确切遗传结构仍不清楚。为了更好地了解该岛屿种群遗传结构的时空变化，我们使用填充标本（1878 - 2001年）以及组织或血液样本（1970 - 2014年）进行了线粒体DNA（mtDNA）分析。我们在该岛屿种群中发现了三种单倍型，其中一种是1997年和2007年样本中的新型mtDNA单倍型。此外，在整个时间跨度内单倍型频率没有明显差异。这些结果表明，该岛屿种群的低遗传变异在过去一百年中持续存在。因此，该岛屿种群几乎不可能孤立地恢复其遗传变异。因此，该物种的保护计划应包括促进大陆和岛屿种群之间的基因交流，例如通过人工引入北海道。
