 They include short RNA sequences, such as microRNAs (miRNAs), small interfering RNAs (siRNAs) and Piwi-interacting RNAs (piRNAs), and long, non-coding RNAs (lncRNA) that may regulate gene expression at different stages of development.Some researchers suggest that instead of the number of genes the focus now should shift to gene interactions and the network of genetic regulatory mechanisms that allow them to support a variety of biological activities.These transitions have taken analysis of genetic complexity from the C-value to the G-value to what some refer to as the I-value, a measure of the total information contained in a genome.