The genetic basis of local adaptation
Natural selection can lead to genetic differentiation between populations for adaptive traits, even in the presence of substantial migration. A classic example in forest trees is adaptation to the steep latitudinal gradient in the length of growing season that characterizes northern environments. Trees often show latitudinal clines in traits, such as the timing of bud set, the onset of flowering and frost hardening. We are investigating the genetic basis of phenological traits that are responsible for climatic adaptations in European aspen (Populus tremula). We are using a collection of P. tremula genotypes (the SwAsp collection) to infer the genetic basis of phenology traits along a latitudinal gradient across Sweden. We are using a combination of association mapping techniques and molecular population genetic studies to link variation in candidate genes to naturally occurring variation in phenology.
The genetic basis of plant defence
Plants have evolved numerous adaptations to defend themselves against attack by herbivores and my group is also studying the genetic basis of plant resistance using the SwAsp collection. We are currently inferring historical patterns of evolution of genes involved in herbivore defence using molecular population genetic methods and using association mapping to dissect naturally occurring variation in herbivore resistance in the SwAsp collection. Many important phenotypic adaptations are mediated by changes in gene regulation, rather than through changes in protein coding sequences, and we are also investigating genes involved in signal transduction pathways that induce wound responses in P. tremula.
- Bernhardsson, C., Robinson, K. M., Abreu, I. N., Jansson, S., Albrectsen, B.R., Ingvarsson, P.K. (2013) Geographic structure in metabolome and herbivore community co-occurs with genetic structure in plant defense genes. Ecology Letters, 16, 791-789.
- Ingvarsson, P.K. and Street, N.R. (2011) Association genetics of complex traits in plants. New Phytologist, 189, 909-922.
- Ma, X-F., Hall. D., St. Onge, K.R., Jansson, S., and Ingvarsson, P.K. (2010) Genetic differentiation, clinal variation and phenotypic associations with growth cessation across the Populus tremula photoperiodic pathway. Genetics, 186, 1033-1044.
- Ingvarsson, P.K. (2008) Multilocus patterns of nucleotide polymorphism and the demographic history of Populus tremula. Genetics, 180, 329-340.
- Ingvarsson, P. K. (2005) Nucleotide polymorphism and linkage disequilibrium within and among natural populations of European aspen (Populus tremula L., Salicaceae). Genetics, 169, 945-953.