Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China.
Centre for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, 666303, China.
Mol Biol Rep. 2022 Feb;49(2):917-929. doi: 10.1007/s11033-021-06911-y. Epub 2021 Nov 6.
Understanding genetic variation is critical for the protection and maintenance of fragmented and highly disturbed habitats. The Taita Hills of Kenya are the northernmost part of the Eastern Arc Mountains and have been identified as one of the world's top ten biodiversity hotspots. Over the past century the current forests in the Taita Hills have become highly fragmented. In order to appraise the influence of anthropological disturbance and fragmentation on plant species in these mountains, we studied the genetic variation and population structure of Dodonaea viscosa (L.) Jacq. (Sapindaceae), using newly developed microsatellite (SSR) markers, combined with ecological niche modelling analyses (ENMs).
We utilized the Illumina paired-end technology to sequence D. viscosa's genome and developed its microsatellite markers. In total, 646,428 sequences were analyzed, and 49,836 SSRs were identified from 42,638 sequences. A total of 18 out of 25 randomly selected primer pairs were designed to test polymorphism among 92 individuals across eight populations. The average observed heterozygosity and expected heterozygosity ranged from 0.119 to 0.982 and from 0.227 to 0.691, respectively. Analysis of molecular variance (AMOVA) revealed 78% variance within populations and only 20% among the eight populations. According to ENM results, D. viscosa's suitable habitats have been gradually reducing since the last glacial maximum (LGM), and the situation will worsen under the extreme pessimist scenario of (representative concentration pathway) RCP 8.5. Moreover, genetic diversity was significantly greater in larger fragments.
In the present study, we successfully developed and tested SSR markers for D. viscosa. Study results indicate that fragmentation would constitute a severe threat to plant forest species. Therefore, urgent conservation management of smaller fragmented patches is necessary to protect this disturbed region and maintain the genetic resources.
理解遗传变异对于保护和维持破碎和高度干扰的栖息地至关重要。肯尼亚的泰塔山是东非大裂谷的最北端，被确定为世界十大生物多样性热点之一。在过去的一个世纪里，泰塔山的现有森林已经高度破碎。为了评估人为干扰和破碎化对这些山脉植物物种的影响，我们使用新开发的微卫星（SSR）标记物，结合生态位模型分析（ENMs），研究了 Dodonaea viscosa（L.）Jacq.（金虎尾科）的遗传变异和种群结构。
我们利用 Illumina 配对末端技术对 D. viscosa 的基因组进行测序并开发了其微卫星标记物。总共分析了 646428 个序列，从 42638 个序列中鉴定出 49836 个 SSR。从 92 个个体的 8 个种群中随机选择 25 对引物，其中 18 对引物设计用于测试多态性。25 对随机引物中，有 18 对引物在 8 个种群的 92 个个体中具有多态性。平均观测杂合度和期望杂合度的范围分别为 0.119 至 0.982 和 0.227 至 0.691。基于 AMOVA 分析，8 个种群内的遗传变异为 78%，种群间的遗传变异为 20%。根据 ENM 结果，自末次冰盛期（LGM）以来，D. viscosa 的适宜栖息地逐渐减少，在代表浓度途径（RCP）8.5 的极端悲观情景下，情况将进一步恶化。此外，较大片段中的遗传多样性显著更高。
在本研究中，我们成功地为 D. viscosa 开发和测试了 SSR 标记物。研究结果表明，破碎化将对植物物种构成严重威胁。因此，迫切需要对较小的破碎斑块进行保护管理，以保护该受干扰地区并维持遗传资源。
