[COLLOQUE] GENTREE Final Conference 27-31 January 2020 séance 5

GENTREE Final Conference :

Pascal MILESI - Uppsala University · Sweden

GENTREE Final Conference 'Genetics to the rescue - managing forests sustainably in a changing environment'

27-31 January 2020, Avignon, France

http://www.gentree-h2020.eu/

Pascal MILESI - Uppsala University · Sweden : Genomic data providesnew insights on the demographic history, local adaptation pattern andgenetic basis of quantitative traits in Norway spruce.

Norway spruce (Picea abies) is a dominant conifer species of majoreconomic importance in northern Europe.

Extensive breeding programswere established to improve phenotypic traits of economic interest.In a first study, based on the exome-sequencing of > 1500 trees,we showed that the origin of the breeding material in southern Swedenwas highly heterogeneous: some were of local origin but many wererecent introductions from the rest of the natural range.

The mixedorigin of the trees together with phenotypic data retrieved from theSwedish breeding program offered a unique opportunity to i)investigate the evolutionary and demographic history of Norway spruce(Chen*, Li*, Milesi* et al. 2019), and ii) dissect the genetic basisof local adaptation of three quantitative traits: height, diameterand bud‐burst (Milesi et al. 2019). First, we reasoned that highpairwise correlations between genotype, phenotype and climaticvariables at origin would not be obtained if the current geneticstructure among populations were only the result of past demographicevents and isolation by distance, reflecting a strong pattern ofadaptation to ancestral environment.

Through genome‐wideassociation studies (GWAS), we then investigated both the geneticbasis of local adaptation to climate and the genetic control of thethree afore-mentioned phenotypic traits in Norway spruce. Inparticular, we showed that the genetic control of growth traits ismuch more polygenic than that of bud‐burst. Our data alsohighlighted how traits with different patterns of geographicalvariation can be used to assess the impact of correction forpopulation structure in GWAS.

From an applied perspective, we arguethat while data from breeding programs might sometimes be incompleteor suboptimal, they are readily available and contain a lot ofvaluable information for evolutionary biologists.