انعطاف پذیری نرخ ترکیب میوزی در پاسخ به درجه حرارت رشادی Plasticity of meiotic recombination rates in response to temperature in Arabidopsis

INTRODUCTION The vast majority of eukaryotes rely on meiosis to produce gametes. One important process within meiosis is the crossing over of homologous chromosomes, which in most eukaryotes is essential for stable chromosome segregation (Zickler and Kleckner 1999). Recombination also shuffles the genetic complements of the two parents of an individual and is thus important in generating novel genetic combinations in gametes and ultimately offspring. The extent and pattern of genetic reshuffling via homologous recombination has important implications for evolution and adaptation, as well as population genetics and breeding (e.g.: Barton 1995; Charlesworth and Barton 1996; Otto 2009; Campos et al. 2015). Recombination is not a static parameter between, or even within taxa. Meiotic recombination rate is known to be sensitive to a variety of environmental factors, particularly temperature (Plough 1917; Elliott 1955; De Storme and Geelen 2014; Bomblies et al. 2015; Modliszewski and Copenhaver 2015; Phillips et al. 2015). Extreme temperatures 36can cause meiotic recombination to fail outright due to structural disruptions of e.g. the spindle, the chromosome axes, or the synaptonemal complex (Bilgir et al. 2013; Bomblies 38 et al. 2015; Morgan et al. 2017). We refer to the temperatures at which such defects become cytologically evident as “failure thresholds.” Less extreme temperature fluctuations that do not cause outright failures, can nevertheless affect the genome-wide recombination rate in diverse taxa ( Plough 1917; Elliott 1955; De Storme and Geelen 2014; Bomblies et al. 2015; Modliszewski and Copenhaver 2015; Phillips et al. 2015). Understanding the nature and strength of these effects has important implications for better understanding and predicting inheritance and evolution, especially in a time of climate change, and also for managing breeding programs. Understanding the effect of temperature on recombination also provides opportunities to manipulate recombination in a targeted and reversible way (e.g. Phillips et al. 2015).