Working with maize , yeast and the weed Arabidopsis , he focuses on the chemical modifications to DNA that determine which genes are active -- a process known as epigenetics .
Martienssen has made major discoveries relating to the way plants control the expression of their genes .
Working with maize , yeast and the weed Arabidopsis , Martienssen focuses on the chemical modifications to DNA that determine which genes are active -- a process known as epigenetics .
Martienssen has made major discoveries relating to the way plants control the expression of their genes .