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核心目标。了解自然界适应的遗传机制对于提高作物产量和保护野生物种也很有用。高纬度地区的生物体面临的挑战之一是冰冻温度。这项研究调查了鼠耳水芹的耐冻性遗传学，鼠耳水芹是许多作物物种的近亲，已成为“模型”生物，并为其开发了许多遗传工具。在早期的工作中，研究人员从意大利和瑞典收集了该物种的种子，并将它们种植在各自国家的实验花园中。他们发现，在瑞典，耐冻性是度过漫长而寒冷的冬天所必需的，而在意大利，耐冻性会降低表现。这一结果体现了生物“权衡”的概念；对一种环境的适应往往会降低其他环境的表现。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特定的环境。该研究调查了耐冻性的遗传控制，并探索了导致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生产在寒冷气候下提高产量的新作物品种的有用工具。此外，研究团队还将开展外展活动，以提高科学素养并促进科学事业。密歇根州立大学的科学家将为 K-12 教师和 W.K. 之间的合作做出贡献。凯洛格生物站制定课程计划，支持下一代科学标准（NGSS）以进行基于探究的学习。该研究采用尖端遗传技术，通过三种互补方法来解决耐冻性的机制和适应性价值。首先，将在瑞典和意大利的两个原始种群中使用在其他同质亲本背景下操纵耐冻基因的新品系进一步检查耐冻性的遗传基础。然后，这些品系将在受控环境室和田间生长，以估计冷冻耐受基因对于跨环境性能的遗传权衡的重要性。其次，将在来自斯堪的纳维亚半岛和西班牙的四个新种群中研究耐冻性的遗传基础，这四个新种群的耐冻性存在显着差异。第三，这项研究将扩大到更广泛的范围，询问在这些重点人群中发现的相同的耐冻基因是否在其他地理区域也存在。第三部分中使用的技术与研究许多人类疾病的遗传学所使用的技术类似。总而言之，这些研究考察了多种自然种群中耐冻性的遗传基础，并评估了这一重要适应性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.