Revolutionary New Finding in Plant Genetics

A landmark study published in Science this month promises to revolutionise our understanding of heritability in plants. Dutch and French researchers have collaborated to show that traits such as flower architecture and the timing of flowering can be determined by epigenetic factors passed down stably from generation to generation.

Epigenetics is an emerging area of interest in the biological and medical sciences. For the past six decades, geneticists have emphasised the impact of inherited changes in DNA on gene expression. However, in recent years, it has become clear that gene expression can also be influenced by “epigenetic” factors such as DNA methylation and histone modification. In mammals, epigenetic marks are usually reset every generation, but there is emerging evidence to support their stable transmission from one generation to the next in some plant species.

The researchers, led by Dr Frank Johannes of the University of Groningen, performed a detailed investigation of epigenetic inheritance of complex traits in inbred strains of the model plant Arabidopsis. After observing a high level of DNA sequence conservation across inbred strains, they hypothesised that differences in plant appearance might stem from stable inheritance of epigenetic marks. Using interval mapping and linkage analysis, the scientists went on to identify several quantitative trait loci, variable epigenetic marks which contribute directly to the expression of particular traits.

Although this result has been obtained in just a single inbred species, with stable inheritance of epigenetic marks assessed over just seven generations, it represents a landmark finding which promises to revolutionise how we think about heritability in flowering plants.