Wednesday, July 19, 2006
Plant genes share the same mechanism found in mammals in the way they are marked or imprinted' to switch on or off depending on their sex, just before fertilisation. Oxford scientists have now shown that differences in the expression states of parental gene copies are not due to actual changes in the genetic code, but to chemical changes in the DNA by a naturally occurring process known as 'methylation'.
Oxford University's Department of Plant Sciences collaborated with scientists from a university in Germany and a biotech company in France (Biogemma) on the study, to be published in Nature Genetics in August.
Researchers investigated the way plant genes are marked, so that only the maternal copies are switched on while the paternal copies are switched off after fertilisation. They analysed two maize 'imprinted' genes in the products of fertilisation - the seed embryo and its accompanying placenta-like structure, the endosperm. They found that the parental copies of these genes that were switched on were not methylated, while those copies that were switched off were methylated.