A case study: looking at the effects of fragmentation on genetic structure in different life history stages of old-growth mountain hemlock (Tsuga mertensiana).
A case study: looking at the effects of fragmentation on genetic structure in different life history stages of old-growth mountain hemlock (Tsuga mertensiana).
复制标题
案例研究：观察破碎对老山铁杉（Tsuga mertensiana）不同生活史阶段遗传结构的影响。
作者：
D. Ally;K. Ritland
为了研究破碎化对山铁杉（Tsuga mertensiana）遗传结构的影响，研究了其在一个老林分和邻近幼苗种群中的精细遗传结构。在5个微卫星位点对306棵古树和195棵自然再生苗进行了基因分型。遗传多样性在早期生长阶段和被清除的幼苗内是相似的。在老年苗成虫级（胸高直径30+ cm）和邻近的自然再生中，发现了显著的近交现象。亲缘性与物理距离有显著的相关性，在最老龄级和相邻裸地的再生苗中均有显著的相关性，而中间龄级则无显著相关性。由于中间阶层没有表现出距离上的隔离，因此产生的关联可能来自于明显发生在干净树木中的单群再生，也可能是在最古老的树木建立起来的时候。亲本分析表明，大规模的碎裂，如这片清晰的，允许增加长距离种子传播。我们的结论是，长寿的树木种群可以由一个群体马赛克组成，反映了碎片化的影响，并导致一个复杂的、年龄依赖的、具有高水平遗传多样性的局部种群结构。
We examined fine-scale genetic structure of mountain hemlock (Tsuga mertensiana) in an old-growth stand and an adjacent seedling population, with the goal of detecting the effects of fragmentation. Three hundred and six old-growth trees and 195 naturally regenerating seedlings were genotyped at 5 microsatellite loci. Genetic diversity was similar across old-growth life stages and within the clear-cut seedlings. Significant inbreeding was found in the adult class (30+ cm diameter at breast height) of old-growth seedlings and in the adjacent natural regeneration. Relatedness was significantly associated with physical distance for both the oldest age class and for regenerating seedlings in the adjacent clear-cut, whereas intermediate classes showed no such association. As intermediate classes show no isolation by distance, the associations that arise probably occur from single cohort regeneration that clearly has taken place in the clear-cut, and possibly when the oldest old-growth trees were established. Parentage analysis suggested that large-scale fragmentation, such as this clear-cut, allowed for increased long-distance seed dispersal. We conclude that long-lived tree populations can consist of a cohort mosaic, reflecting the effects of fragmentation, and resulting in a complex, age-dependent, local population structure with high levels of genetic diversity.
影响因子：
3.3
作者：
M. Lynch;K. Ritland
通讯作者：
M. Lynch;K. Ritland