Evolutionary genetics of adaptation in natural populations of Arabidopsis thaliana

了解生物体如何适应它们在自然界中经历的许多挑战是生物学的一个中心目标。了解自然界适应的遗传机制也有助于提高作物产量和保护野生物种。高纬度生物面临的一个这样的挑战是冰冻温度。这项研究调查了老鼠耳水芹耐寒的遗传学，它是许多作物物种的近亲，已经成为许多遗传工具已经开发出来的“模式”生物。在早期的工作中，研究人员从意大利和瑞典收集了这种物种的种子，并将它们种植在这两个国家的实验花园中。他们发现，在瑞典漫长而寒冷的冬天需要耐寒，而在意大利，耐寒会降低表现。这一结果说明了生物“权衡”的概念；适应一种环境往往会降低其他地方的表现。这个简单的原理可以解释为什么地球上有这么多不同的物种，因为每个物种都适应了特定的环境。这项研究调查了耐寒性的基因控制，并探索了影响跨环境性能权衡的机制。这些研究中确定的遗传机制可能是在寒冷气候下培育产量更高的新作物品种的有用工具。此外，研究小组将开展促进科学素养和促进科学职业生涯的外联活动。密歇根州立大学的科学家们将为K-12教师和W.K.凯洛格生物站之间的合作做出贡献，以开发支持下一代科学标准(NGSS)的探究式学习的教案。这项研究利用尖端基因技术，通过三种互补的方法来研究耐寒性的机制和适应价值。首先，将在瑞典和意大利的两个原始种群中进一步研究耐冻性的遗传基础，使用在其他相同的亲本背景中操纵耐冻性基因的新品系。然后，这些品系将在受控环境室和田间种植，以评估耐冻基因在不同环境中表现的遗传权衡的重要性。其次，将在来自斯堪的纳维亚和西班牙的四个新种群中调查耐寒的遗传基础，这些种群的耐寒能力存在显著差异。第三，这项研究将扩大到更广泛的范围，询问是否在其他地理区域发现了在这些局部人群中发现的相同的耐寒基因。第三部分使用的技术类似于用于研究许多人类疾病的遗传学的技术。综上所述，这些研究考察了在广泛的自然种群中耐寒的遗传基础，并评估了这一重要适应特征的性能权衡机制。

Understanding how organisms adapt to the many challenges they experience in nature is a central goal in biology. Knowledge of the genetic mechanisms underlying adaptation in nature is also useful for increasing crop yields and for the conservation of wild species. One such challenge faced by organisms at high latitudes is freezing temperatures. This research investigates the genetics of freezing tolerance in the mouse-eared cress, a relative of many crop species that has become a "model" organism for which many genetic tools have been developed. In earlier work, the researchers collected seeds of this species from Italy and Sweden and planted them in experimental gardens located in each country. They found that freezing tolerance is required to survive the long, cold winters in Sweden, whereas freezing tolerance reduces performance in Italy. This result exemplifies the concept of biological "trade-offs"; adaptation to one environment often reduces performance elsewhere. This simple principle can explain why there are so many different species on earth, in that each species is adapted to a particular environment. The research investigates the genetic control of freezing tolerance and explores the mechanisms that contribute to the tradeoff in performance across environments. The genetic mechanisms identified in these studies may be useful tools for producing new crop varieties with increased yield in cold climates. In addition, the research team will perform outreach activities that advance scientific literacy and promote careers in science. Michigan State University scientists will contribute to a partnership between K-12 teachers and the W.K. Kellogg Biological Station to develop lesson plans that support Next Generation Science Standards (NGSS) for inquiry based learning.The research employs cutting edge genetic technologies to address the mechanisms and adaptive value of freezing tolerance using three complementary approaches. First, the genetic basis of freezing tolerance will be further examined in the two original populations in Sweden and Italy using new lines manipulating freezing tolerance genes in otherwise homogeneous parental backgrounds. These lines will then be grown in controlled environment chambers and in the field to estimate the importance of freezing tolerance genes for genetic trade-offs in performance across environments. Second, the genetic basis of freezing tolerance will be investigated in four new populations from Scandinavia and Spain with dramatic differences in freezing tolerance. Third, this research will be expanded to an even broader scale, asking if the same genes for freezing tolerance found in these focal populations are found in other geographic regions. The techniques employed in part three are similar to those used to study the genetics of many human diseases. Taken together, these studies examine the genetic basis of freezing tolerance in a broad diversity of natural populations and assess the mechanisms of performance trade-offs for this important adaptive trait.