(CNN)Mourners held a heavenly birthday memorial Sunday for Victoria Martens, the 10-year-old New Mexico girl who Albuquerque police say was raped by her mother's boyfriend and then killed while her mother watched.
RNA interference (RNAi) is a natural process that cells use to 'turn off' or silence unwanted or harmful genes. The initial discovery of this phenomenon was in 1991, by scientists trying to deepen the colour of petunias. Surprisingly, by introducing a gene for colour, they found that they had turned off the gene.
This RNA-containing complex can then inhibit transcription of an mRNA molecule that has a sequence complementary to its RNA component. siRNAs were first defined by their participation in RNA interference (RNAi). They may have evolved as a defense mechanism against double-stranded RNA viruses.