Periodic Reporting for period 3 - ANGI (Adaptive significance of Non Genetic Inheritance)
Reporting period: 2019-03-01 to 2020-08-31
Why will this project have a broad impact on life sciences?
This project will integrate new findings into an inclusive theory of natural selection.
Genetic diversity is the key parameter used to study the evolution of species, predict their adaptive potential, manage genetic resources in agronomy, plan biological conservation strategies and communicate with a general audience on these topics. There is an emerging demand for clarifications about the role of the transgenerational environmental effects on the response to selection and more generally on the adaptive potential. There is also a demand by fundamental researchers to account for these effects in quantitative estimates and parameterize models of adaptive dynamics. Evolutionary biologists investigating the paradoxical absence of genetic evolution in response to selection in natural populations are also calling for empirical data on environmental effects shortcutting genetic selection. The ANGI project will participate to answer those demands.
We have conducted five exhaustive surveys (2016-2020) of the six natural populations occurring in the fragmented habitat of the abandoned saltmarsh between Peyriac de Mer and Bages in Southern France and characterized 15000 plants in natural populations (phenotype, geographic coordinates, 25 genetic [microsatellite] marker genotypes, microenvironment on the basis of photos). We have mapped the geographic patches were environmental conditions are more likely to be shared (e.g. open habitat on rocks, grassland). We are currently constructing the pedigree by genetically assigning parenthood to reach 3000 plants included in a highly reliable pedigree.
Experiments in controlled conditions allowed us to expose plants to different treatments (different levels of shade exposure and climate conditions). Experiments conducted in natural conditions were used to identify traits that might be involved with snapdragon plant adaptive evolution. Other experiments conducted in more controlled conditions (greenhouse and growth chambers) were conducted to test for an epigenetic basis of trait variation, with a focus on the developmental response to shade of snapdragon plants. We used Antirrhinum majus highly inbred lines and Arabidopsis thaliana Recombinant Inbred Lines, where the genome was fixed by generations of self-fertilization into a homozygous state, to investigate fundamental ecological and evolutionary mechanisms related to epigenetic trait variation.
In terms of results linked to the study of natural populations (WP1-2-3), we have obtained preliminary results and are extending the datasets to reach an acceptable level of statistical power and prepare scientific publications. These results indicate low connectivity between fragmented populations, heterogeneous selection, and low genetic heritability for fitness related traits.
In terms of results linked to experimental approaches (WP4), we have obtained several results that were published or submitted for publication. These results show that snapdragon plants exhibit strong phenotypic plasticity in response to shade (SLA, stem elongation in response to shade, etc.). Although we detected a strong phenotypic response, and detected some epigenetic changes in methylation patterns, our findings collectively point out towards an only small potential epigenetic variation associated with the snapdragon plant response to shade.
In terms of results linked to theoretical and conceptual developments (WP5). We have developed and published a methodological guide and opinion papers on how and why the potential role of epigenetic and genetic variation in the response to selection should be studied simultaneously and what are the potential implications for agronomic sciences.