Epigenetic inheritance in asexual dandelions
Koen Verhoeven
Netherlands Institute of Ecology, dept. Terrestrial Ecology, the Netherlands
Epigenetic mechanisms such as DNA methylation can cause stable but reversible changes in gene activity without changes in the underlying DNA sequence. Recent studies in plants have shown that DNA methylation patterns can be modified by environmental and genomic stresses, that they can be transmitted between generations and that they can cause heritable trait variation in absence of genetic (sequence) variation. This implies that heritable variation may not be fully understood from genetic variation alone. To date, however, the evolutionary relevance of epigenetic inheritance is unknown and much of the underlying mechanisms remains poorly understood. To gain better insight in the factors that generate heritable methylation variation I used methylation-sensitive AFLP markers to evaluate the epigenetic consequences of ecological stress exposure and polyploidization events in apomictic dandelions. Especially stress exposure triggered methylation changes and most of these changes were faithfully transmitted to unexposed offspring. This suggests that heritable methylation variation is readily generated that is independent of genetic variation between individuals, which can have consequences for the adaptive potential of asexual species such as dandelions. I will briefly sketch some perspectives for linking epigenetics and ecological research, which can improve our understanding of the evolutionary relevance of epigenetic inheritance.
Koen Verhoeven
Netherlands Institute of Ecology, dept. Terrestrial Ecology, the Netherlands
Epigenetic mechanisms such as DNA methylation can cause stable but reversible changes in gene activity without changes in the underlying DNA sequence. Recent studies in plants have shown that DNA methylation patterns can be modified by environmental and genomic stresses, that they can be transmitted between generations and that they can cause heritable trait variation in absence of genetic (sequence) variation. This implies that heritable variation may not be fully understood from genetic variation alone. To date, however, the evolutionary relevance of epigenetic inheritance is unknown and much of the underlying mechanisms remains poorly understood. To gain better insight in the factors that generate heritable methylation variation I used methylation-sensitive AFLP markers to evaluate the epigenetic consequences of ecological stress exposure and polyploidization events in apomictic dandelions. Especially stress exposure triggered methylation changes and most of these changes were faithfully transmitted to unexposed offspring. This suggests that heritable methylation variation is readily generated that is independent of genetic variation between individuals, which can have consequences for the adaptive potential of asexual species such as dandelions. I will briefly sketch some perspectives for linking epigenetics and ecological research, which can improve our understanding of the evolutionary relevance of epigenetic inheritance.
