A MAGIC design to examine natural variation in photosynthesis and nutrition in Chlamydomonas

Extensive genetic variation has been uncovered among Chlamydomonas laboratory and natural strains, which is valuable to dissect polygenic quantitative traits. Multi-Parent Advanced Generation Inter-Cross (MAGIC) populations are instrumental biological resources to exploit genetic variation in model organisms and map loci underlying traits of interest. Here, we present a MAGIC population for Chlamydomonas consisting of > 700 F8 progeny obtained from crossing 8 genetically diverse founder strains. We will describe a detailed phenotypic characterization of MAGIC population of growth, chlorophyll fluorescence-based photosynthetic parameters (rETR-PSII, NPQ) and elemental composition in TAP, TMP and 4 mineral deficiency culture conditions. The MAGIC population displays phenotypic variation that by far exceeds the diversity found in the parents, indicating that new genetic variation has been created within the population. The MAGIC population has been genotyped by whole genome re-sequencing revealing the genetic architecture of the population, with a contribution of each founder ranging between 10.3-15.6% on average to the genome of the progeny. The identification of the genomic regions associated with variations in the traits of interest is underway and preliminary data will be presented. We will also discuss how to make this resource available for the Chlamydomonas community.