Martins K, Chaves L J, Vencovsky R, Kageyama P Y
Universidade Federal de São Carlos, Campus Sorocaba, Sorocaba, SP, Brasil.
Genet Mol Res. 2011 Apr 19;10(2):665-77. doi: 10.4238/vol10-2gmr1046.
Solanum lycocarpum (Solanaceae) is a woody species found in the Brazilian Cerrado. The flowers are pollinated by Xylocopa spp bees, and seeds are dispersed by mammals with distinct home range sizes. As a consequence, relative contributions of pollen and seeds to overall gene flow can vary according to different spatial scales. We studied the genetic structure of four natural populations of S. lycocarpum separated by 19 to 128 km, including individuals located along dirt roads that interlink three of the populations. A total of 294 individuals were genotyped with five nuclear and six chloroplast microsatellite markers. Significant spatial genetic structure was found in the total set of individuals; the Sp statistic was 0.0086. Population differentiation based on the six chloroplast microsatellite markers (θ(pC) = 0.042) was small and similar to that based on the five nuclear microsatellite markers (θ(p) = 0.054). For this set of populations, pollen and seed flow did not differ significantly from one another (pollen-to-seed flow ratio = 1.22). Capability for long distance seed dispersion and colonization of anthropogenic sites contributes to the ability of S. lycocarpum to maintain genetic diversity. Seed dispersion along dirt roads may be critical in preserving S. lycocarpum genetic diversity in fragmented landscapes.
光果龙葵（茄科）是一种生长在巴西塞拉多的木本植物。其花朵由木蜂属蜜蜂授粉，种子由具有不同活动范围大小的哺乳动物传播。因此，花粉和种子对总体基因流的相对贡献可能会因不同的空间尺度而有所不同。我们研究了四个自然分布的光果龙葵种群的遗传结构，这些种群相隔19至128公里，其中包括分布在连接其中三个种群的土路沿线的个体。总共使用五个核微卫星标记和六个叶绿体微卫星标记对294个个体进行了基因分型。在所有个体中发现了显著的空间遗传结构；Sp统计量为0.0086。基于六个叶绿体微卫星标记的种群分化（θ(pC)=0.042）较小，与基于五个核微卫星标记的种群分化（θ(p)=0.054）相似。对于这组种群，花粉流和种子流之间没有显著差异（花粉与种子流比率=1.22）。长距离种子传播能力和对人为干扰地点的定殖能力有助于光果龙葵维持遗传多样性。沿着土路的种子传播对于在破碎景观中保护光果龙葵的遗传多样性可能至关重要。
