Here are some interpretations of Jnanamudra:

Thumb – Consciousness
Index Finger – Jiva
Other Three Fingers – Body (Tamas), Mind (Rajas), Intellect (Sattva)

Variation I

Index finger separating from other three fingers and bowing to the thumb – Jiva surrenders to the Consciousness.

Variation II

Index finger separating from other three fingers and meeting the thumb at the top –  Jiva recognises that it is different from body, mind, intellect and realises unity with the Consciousness.