A0564
Title: Genetic adaptations in the population history of Arabidopsis thaliana
Authors: Hirohisa Kishino - Chuo University (Japan) [presenting]
Reiichiro Nakamichi - Japan Fisheries Research and Education Agency (Japan)
Shuichi Kitada - Tokyo University of Marine Science and Technology (Japan)
Abstract: During the course of its range expansion or due to an environmental change, the population of Arabidopsis thaliana encountered unexperienced biotic and abiotic stresses. The dynamics of the allele frequencies at the 89,786 QTLs of 248 traits and 21,914 eQTLs of 2,879 genes identified 650 phenotypic adaptations (p-adaptations) and 3,925 gene expression-adaptations (e-adaptations) (FDR=0.05) were analyzed. The population accomplished large-scale p-adaptations and e-adaptations along four lineages, the eastward migration to Central Asia, northward migration to Scandinavia, migration to Azerbaijan, and migration into the United States. Extremely cold winters and short summers extended seed dormancy and expanded the root system architecture. Low temperatures lengthened the growth periods, and low light intensity necessitated increased chloroplast activity. The subtropical and wet environment enhanced phytohormone signalling pathways, responding to the biotic and abiotic stresses. Being exposed to heavy metals, the alleles underlying lower uptake from the soil, lower growth rate, lower resistance to bacteria, and higher expression of photosynthetic genes were selected. In total, 34,885 changes in allele frequencies were identified beyond the level of genetic drift (FDR=0.05). The database of QTLs and eQTLs combined with climatic information enabled a knowledge-based population genomic analysis, providing a clue for understanding the complex history of biological adaptation.
