The forty-first Gene Key is given a special position in both modern systems, and the reason is worth tracing because it shows how a structural claim travels.
In Human Design, Gate 41 is held to begin the cycle of all sixty-four. Ra Uru Hu described it by analogy with a start codon, the triplet at which the reading of a gene begins, and gave it priority accordingly: it sits in the Root as pressure, and the fantasy and anticipation it carries are the pressure to begin experiencing at all before there is anything to experience.
The Gene Keys inherits the claim. Rudd's forty-first key runs from fantasy through anticipation to emanation, and emanation is his word for the source from which experience issues, which preserves the sense of a beginning-point.
In the I Ching, the forty-first hexagram is Decrease. Its counsel concerns sacrifice offered sincerely with limited means, and its structural position in the King Wen sequence is ordinary; it pairs with the forty-second, Increase, in the usual way of that sequence and starts nothing. There is no Chinese tradition in which hexagram forty-one begins a cycle.
So the priority is an architectural decision made by Ra Uru Hu in 1987 and carried over by Richard Rudd two decades later. It is entirely internal to the modern systems.
This is a useful case to hold on to, because it is the pattern in miniature. A claim originates in a twentieth-century revelation, is inherited by a twenty-first-century derivative, appears in both, and thereby acquires the look of something long established. Two sources agreeing is not corroboration when one of them got it from the other.
Sources The Human Design SystemRa Uru Hu (Alan Robert Krakower) with Gene Keys: Embracing Your Higher PurposeRichard Rudd, The I Ching, or Book of ChangesRichard Wilhelm (trans.); Cary F. Baynes (English trans.)