Collevatti Rosane G, Lima Jacqueline S, Ballesteros-Mejia Liliana
Laboratório de Genética and Biodiversidade, ICB, Universidade Federal de Goiás (UFG), Goiânia, Brazil.
Front Genet. 2019 Sep 5;10:788. doi: 10.3389/fgene.2019.00788. eCollection 2019.
Restricted gene flow may lead to the loss of genetic diversity and higher genetic differentiation among populations, but the genetic consequences of megafauna extinction for plant populations still remain to be assessed. We performed a phylogenetic-independent meta-analysis across 102 Neotropical plants to test the hypothesis that plant species with megafaunal seed dispersal syndrome have a lower genetic diversity and a higher genetic differentiation than those without it. We classified as megafauna-dependent plant species those that potentially relied only on megafauna to seed dispersal, and as megafauna-independent those that relied on megafauna and other seed dispersers. Our data comprised 98 studies using microsatellite markers. We found no statistical difference in genetic diversity and differentiation between plants with megafauna and non-megafauna seed dispersal syndrome, although the statistical power to detect differences in genetic differentiation was low. Moreover, we found no statistical difference between megafauna-dependent and megafauna-independent plant species. We then used generalized linear mixed models and phylogenetic generalized least square models to investigate the effects of megafaunal seed dispersal syndromes and reproductive traits on variation in genetic diversity and genetic differentiation. We found no effect of megafaunal syndrome, rather, reproductive traits, such as pollination mode, mating, and breeding systems, showed significant effects. Our findings show that the genetic studies of Neotropical plants performed so far show no difference in genetic diversity and differentiation in plants with megafaunal compared to those with non-megafaunal seed dispersal syndromes. Our results also provide evidence pointing out that plant species with megafaunal seed dispersal syndromes may have used different strategies to counterbalance the extinction of their mutualistic megafauna dispersers, such as the dispersal by extant mammals that may promote long-distance seed dispersal. Our results also reinforce the importance of pollination to long-distance gene flow in Neotropical plants.
基因流受限可能导致遗传多样性丧失以及种群间遗传分化加剧，但大型动物灭绝对植物种群的遗传影响仍有待评估。我们对102种新热带植物进行了系统发育独立的荟萃分析，以检验以下假设：具有大型动物种子传播综合征的植物物种比没有该综合征的植物物种具有更低的遗传多样性和更高的遗传分化。我们将那些可能仅依赖大型动物进行种子传播的植物物种归类为依赖大型动物的植物物种，而将那些依赖大型动物和其他种子传播者的植物物种归类为不依赖大型动物的植物物种。我们的数据包括98项使用微卫星标记的研究。我们发现，具有大型动物和不具有大型动物种子传播综合征的植物在遗传多样性和分化方面没有统计学差异，尽管检测遗传分化差异的统计效力较低。此外，我们发现依赖大型动物和不依赖大型动物的植物物种之间没有统计学差异。然后，我们使用广义线性混合模型和系统发育广义最小二乘模型来研究大型动物种子传播综合征和繁殖性状对遗传多样性和遗传分化变异的影响。我们发现大型动物综合征没有影响，相反，繁殖性状，如授粉方式、交配和育种系统，显示出显著影响。我们的研究结果表明，迄今为止对新热带植物进行的遗传研究表明，具有大型动物种子传播综合征的植物与具有非大型动物种子传播综合征的植物在遗传多样性和分化方面没有差异。我们的结果还提供了证据表明，具有大型动物种子传播综合征的植物物种可能采用了不同的策略来平衡其共生大型动物传播者的灭绝，例如通过现存哺乳动物进行传播，这可能促进远距离种子传播。我们的结果还强化了授粉对新热带植物远距离基因流的重要性。
