Fuchs Eric J, Cascante-Marín Alfredo, Madrigal-Brenes Ruth, Quesada Mauricio
Escuela de Biología, Universidad de Costa Rica, Ciudad Universitaria Rodrigo Facio, San Pedro Montes de Oca 11501-2060, Costa Rica.
Laboratorio Nacional de Análisis y Síntesis Ecológica, Escuela Nacional de Estudios Superiores Unidad Morelia, Universidad Nacional Autónoma de México, Morelia, Michoacán, 58190, México.
AoB Plants. 2022 Dec 17;15(1):plac060. doi: 10.1093/aobpla/plac060. eCollection 2023 Jan.
Gene flow connects populations and is necessary to sustain effective population sizes, and genetic diversity. In the Lower Central American (LCA) region, the complex topographic and climatic history have produced a wide variety of habitats resulting in high biodiversity. Phylogeographic studies of plants from this area are scarce, and to date none have been conducted on palms. We used SSR and chloroplast DNA (cpDNA) markers to study the genetic diversity and structure of populations of the understory palm in Costa Rica. We found that populations of have moderate to high nuclear simple sequence repeat (SSR) genetic diversity, likely due to large population sizes and its outcrossing mating system. Habitat loss and fragmentation may have contributed to increased genetic structure within slopes. High-elevation mountain ranges appeared to be a significant barrier for gene flow among populations in the Caribbean and Pacific slopes; however, ranges are permeable through low-elevation passes. In contrast, most populations had a single distinct cpDNA haplotype, supporting the hypothesis of several isolated populations that experienced decline that likely resulted in eroded cytoplasmic genetic diversity within populations. The haplotype network and Bayesian analysis linked populations in the Caribbean and the southern Pacific coast, suggesting that gene flow between Pacific and Caribbean populations may have occurred through the southern extreme of the Talamanca Mountain range in Panama, a colonization pathway not previously suggested for LCA plants. This is one of the first phylogeographic studies conducted on tropical palms in the LCA region and the first in the genus , which sheds light on possible gene flow and dispersal patterns of in Costa Rica. Our results also highlight the importance of mountain ranges on shaping gene flow patterns of Neotropical plants.
基因流连接着种群，对于维持有效种群大小和遗传多样性至关重要。在中美洲低地（LCA）地区，复杂的地形和气候历史造就了多种多样的栖息地，从而产生了高度的生物多样性。对该地区植物的系统地理学研究很少，迄今为止尚未对棕榈进行过此类研究。我们使用简单序列重复（SSR）和叶绿体DNA（cpDNA）标记来研究哥斯达黎加林下棕榈种群的遗传多样性和结构。我们发现，该棕榈种群具有中度到高度的核简单序列重复（SSR）遗传多样性，这可能归因于其较大的种群规模和异交交配系统。栖息地丧失和破碎化可能导致了山坡内遗传结构的增加。高海拔山脉似乎是加勒比和太平洋山坡种群间基因流的一个重要障碍；然而，山脉通过低海拔通道是可渗透的。相比之下，大多数种群具有单一独特的cpDNA单倍型，这支持了几个孤立种群经历衰退的假说，这可能导致了种群内细胞质遗传多样性的侵蚀。单倍型网络和贝叶斯分析将加勒比地区和太平洋南部海岸的种群联系起来，表明太平洋和加勒比种群之间的基因流可能是通过巴拿马塔拉曼卡山脉的最南端发生的，这是此前未被提出的LCA植物的一种殖民途径。这是在LCA地区对热带棕榈进行的首批系统地理学研究之一，也是该属的首次研究，它揭示了哥斯达黎加该棕榈可能的基因流和扩散模式。我们的结果还突出了山脉对塑造新热带植物基因流模式的重要性。
