An overview of natural variation studies in the Arabidopsis thaliana circadian clock

• Natural variation in Arabidopsis can be used to identify novel clock components and new structural understanding of known components.
• We summarize previous attempts to detect components for light and temperature input to the clock.
• We discuss the future demands of quantitative genetic studies of the clock in the era of second-generation sequencing.

Circadian clocks are ubiquitous mechanisms that provide an adaptive advantage by predicting subsequent environmental changes. In the model plant Arabidopsis thaliana (Arabidopsis), our understanding of the complex genetic network among clock components has considerably increased during these past years. Modeling has predicted the possibility of additional component to systematically and functionally complete the clock system. Mutagenesis screens have in the past been successfully employed to detect such novel components. With the advancement in sequencing technologies and improvements in statistical approaches, the extensive natural variation present in Arabidopsis accessions has emerged as a powerful alternative in functional gene discovery. In this review article, we review the previous efforts in mapping natural alleles affecting various clock parameters and will discuss further potentials of such natural-variation studies in physiological and ecological contexts.