Materialistic science has only identified forty-six chromosomes as related to physicality (the three dimensional world, the sephirah Malkuth). Modern science remains unaware of the vital or ethereal aspect of our physiology (the fourth dimensions, the sephirah Yesod) in which there are two additional chromosomes, making the actual number forty-eight. This corresponds to the forty-eight laws of the microcosm and hydrogen 48.
"The sixth cosmic order—any human organism—is definitely controlled by forty-eight laws. We can see that this is totally proven in the human germinal cell, since this is constituted—as it is already known—by forty-eight chromosomes..." - Samael Aun Weor, Hell, the Devil, and Karma