[COLLOQUE] GENTREE Final Conference 27-31 January 2020 séance 29

GENTREE Final Conference : Juan Pablo JARAMILLO-CORREA - UNAM Mexico City · Mexico

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/

Juan Pablo JARAMILLO-CORREA - UNAM Mexico City · Mexico : Evaluating the accuracy of genomic prediction for the management and conservation of small secluded natural tree populations mall isolated populations are threatened by the action of inbreeding and genetic drift, which may lead to the accumulation of (partially) deleterious variants and compromise survival.

In forest trees, such effects can be counteracted by large seedoutput over long periods of time, combined with strong selectivepressures against inbreds

-(1). Such a drift-selection balance isexpected to maintain overly constant levels of genetic variation

-(2),and even facilitate local adaptation

-(3), particularly when selectiveregimes are constant over time. However, under strong inbreedingregimes, inbreeding depression posses a serious threat, and assistedmigration has been proposed to “genetically rescuing” suchpopulations, at the expense of outbreeding depression risks (i.e.introducing maladapted individuals;

-4). Genomic prediction models(GPM) are built for small breeding populations submitted to strongartificial selection in domesticated taxa.

They aim predictingphenotypic performance from genomic information, for ultimatelyincreasing genetic gain.

When combined with genomic associationstudies (GWAS), this methodology is expected to enhance geneticimprovement and reduce breeding cycle length (5).

Whether thisapproach can be extended for the management and conservation ofnatural populations and guide assisted migration programs, is still apending question.

The rationale is that historically smallpopulations can be viewed as natural ‘mimics’ of breedingpopulations in domestication programs, such that historicalrecombination and selective regimes have produced non-randomgenotype-phenotype associations, which can be integrated into GPMs.

We tested such possibility within natural populations of Sacred fir(Abies religiosa; Pinaceae) in central Mexico, to study growth andphysiological traits in a multi-environment test-trial. We genotypedover 200 naturally re-generated and introduced individuals for 2,286single nucleotide polymorphisms (SNP), derived from genotyping bysequencing.

These markers were used to develop GPMs for each trait.

After testing different training and validation datasets, anddetermining the models’ predictive ability with randomization andcross-validation techniques, the highest predictabilities (R2;ranging between 0.3 and 0.45) were obtained for growth characters.

They were similar to those previously reported for forest treesundergoing selective breeding (5, 6, 7). The best models were alwaysthose built for natural saplings and used to predict the performanceof introduced individuals in the same environment.

Integratingmicroenvironmental soil variability allowed detectinggenotype-phenotype interactions, which further increasedpredictability.

Our results open a promising avenue for implementingGPMs in management and conservation programs of natural populations(see also 8), particularly for non-model species with poorlydeveloped genomic resources. Such models should be particularlyuseful for predicting the performance on introduced seedlings andguiding assisted migration programs.