I'm working on a project on siRNA designing. For that I needed a clear concept of its cellular origin and mechanism. But in case of segregating the two strands of siRNA duplex as one 'guide strand' and another 'passenger strand', which mechanism is followed by RISC complex? In reviewing the literature, I got stuck in two different opinions about it. I'm providing here exactly what they said about it. One source stated - " The strand that is thermodynamically less stable due to its base pairing at the 5´end is chosen to remain part of the RISC-complex " But another source said - " Within the RISC complex, siRNA strands are separated and the strand with the more stable 5′-end is typically integrated to the active RISC complex." I'm so confused about it! Which one is correct - less stable/more stable?