Calsbeek Brittny, Lavergne Sebastien, Patel Manisha, Molofsky Jane
Department of Genetics, North Carolina State University Raleigh, NC, USA.
Laboratoire d'Ecologie Alpine, Université Joseph Fourier CNRS, Grenoble, France.
Evol Appl. 2011 Nov;4(6):726-35. doi: 10.1111/j.1752-4571.2011.00195.x. Epub 2011 Jun 24.
Evolutionary processes such as migration, genetic drift, and natural selection are thought to play a prominent role in species invasions into novel environments. However, few empirical studies have explored the mechanistic basis of invasion in an evolutionary framework. One promising tool for inferring evolutionarily important changes in introduced populations is the genetic variance-covariance matrix (G matrix). G matrix comparisons allow for the inference of changes in the genetic architecture of introduced populations relative to their native counterparts that may facilitate invasion. Here, we compare the G matrices of reed canary grass (Phalaris arundinacea L.) populations across native and invasive ranges, and between populations along a latitudinal gradient within each range. We find that the major differences in genetic architecture occur between populations at the Northern and Southern margins within each range, not between native and invasive populations. Previous studies have found that multiple introductions in introduced populations caused an increase in genetic variance on which selection could act. In addition, we find that differences in the evolutionary potential of Phalaris populations are driven by differences in latitude, suggesting that selection also shapes the evolutionary trajectory of invasive populations.
诸如迁移、遗传漂变和自然选择等进化过程被认为在物种入侵新环境中起着重要作用。然而，很少有实证研究在进化框架内探究入侵的机制基础。推断引入种群中具有进化重要性变化的一个有前景的工具是遗传方差协方差矩阵（G矩阵）。G矩阵比较能够推断引入种群相对于其原生对应种群在遗传结构上的变化，这些变化可能促进入侵。在这里，我们比较了芦苇状金丝雀草（Phalaris arundinacea L.）在原生和入侵范围内的种群的G矩阵，以及每个范围内沿纬度梯度的种群之间的G矩阵。我们发现，遗传结构的主要差异出现在每个范围内南北边缘的种群之间，而非原生种群和入侵种群之间。先前的研究发现，引入种群中的多次引入导致了可被选择作用的遗传方差增加。此外，我们发现芦苇状金丝雀草种群进化潜力的差异是由纬度差异驱动的，这表明选择也塑造了入侵种群的进化轨迹。
