也门索科特拉岛龙血树的遗传密码与保护希望
On the parched limestone plateaus of Socotra, an archipelago adrift in the Indian Ocean, the dragon’s blood tree (Dracaena cinnabari) stands as a living fossil — its umbrella-like canopy and crimson resin have captivated naturalists for centuries. Yet beneath its otherworldly silhouette lies a genetic puzzle that scientists are only beginning to decode. Endemic to this Yemeni island, the species has evolved in near-total isolation, resulting in a genome shaped by harsh aridity and episodic drought. Recent field expeditions, however, have revealed troubling signs: seedlings are scarce, and adult trees are succumbing to fungal pathogens and rising temperatures. Understanding the tree’s genetic diversity has become an urgent prerequisite for any conservation strategy.
The island’s unique biogeography — a fragment of the ancient Gondwana supercontinent — makes its flora a living laboratory for evolutionary biology. Dragon’s blood populations are not continuous but fragmented across microclimates, from mist-soaked highlands to sun-baked escarpments. This patchy distribution, combined with limited seed dispersal by birds and wind, has created distinct genetic clusters. Using microsatellite markers and chloroplast DNA sequencing, researchers have identified surprisingly low heterozygosity in some stands — a signal of inbreeding that may foreshadow reduced resilience. Such bottlenecks, they argue, could amplify the threat posed by the region’s intensifying heatwaves and erratic monsoon patterns.
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