Both the Tetrad and Sigé appear in the context as if they made revelations to Marcus, but (what has not been sufficiently observed) in different ways.
Tetrad |
Each player is given a pile of blocks that resemble Tetrads .
In crossing-over, a Spo11 enzyme makes staggered nicks in a pair of sister chromatid strands (in a tetrad organization of prophase).
Variation of the first term of the action with respect to the tetrad gives the (mixed index) Einstein tensor and variation of the second term with respect to the tetrad gives a quantity that vanishes by symmetries of the Riemann tensor (specifically the first Bianchi identity), together these imply Einstein's vacuum field equations hold.