近日，墨尔本大学Andrew R. Weeks及其课题组发现突破瓶颈：考拉（Phascolarctos cinereus）遗传恢复的人口路径。这一研究成果于2026年3月5日发表在国际顶尖学术期刊《科学》上。

研究利用418只考拉的全基因组数据，小组发现遗传多样性较高的种群携带最大的突变负荷，有效种群大小（Ne）下降，而历史瓶颈但正在恢复的种群显示出突变负荷降低，Ne增加，并再生新的罕见变异。小组得出结论，这种模式是由于快速的人口扩张，通过重组重组遗传变异，比传统的多样性指标更快地影响了Ne。他们的发现表明，瓶颈种群的恢复可以通过快速的人口增长来实现，这可以在受威胁的种群中重建进化潜力。

研究人员表示，人口瓶颈会侵蚀遗传多样性，加剧近亲繁殖，从而导致进化的死胡同。尽管理论预测了可能的逃逸路线，但对这一过程的直接观测很少。

附：英文原文

Title: Escaping bottlenecks: The demographic path to genetic recovery in koalas (Phascolarctos cinereus)

Author: Collin W. Ahrens, Adam D. Miller, Luke W. Silver, Elspeth A. McLennan, Carolyn J. Hogg, Andrew R. Weeks

Issue&Volume: 2026-03-05

Abstract: Population bottlenecks can lead to evolutionary dead ends by eroding genetic diversity and intensifying inbreeding. Although theory predicts possible escape routes, direct observations of this process are rare. Using whole-genome data from 418 koalas, we found that populations with higher genetic diversity harbored the greatest mutational loads and had declining effective population sizes (Ne), whereas historically bottlenecked but recovering populations displayed reduced mutational load, exhibited increasing Ne, and regenerated new, rare variants. We concluded that this pattern was due to rapid demographic expansion, which reshuffled genetic variation through recombination and affected Ne more quickly than it did conventional diversity metrics. Our findings suggest that recovery of bottlenecked populations can occur through rapid demographic growth and that this can reestablish evolutionary potential in threatened populations.

DOI: adz1430

Source: https://www.science.org/doi/10.1126/science.adz1430