We just threw out a major rule of biology; it turns out nature has a much weirder way of keeping species diverse than we ever imagined.
April 13, 2026
Original Paper
The geometry of dominance shows broad potential for stable polymorphism under antagonistic pleiotropy
bioRxiv · 10.64898/2026.03.27.714876
The Takeaway
For a long time, scientists thought that genes with both "good" and "bad" effects couldn't easily maintain variety in a species. This study proves that the geometry of how these traits interact actually encourages diversity, solving a long-standing puzzle of evolution.
From the abstract
Alleles with opposing effects on fitness characters are said to exhibit selectional antagonistic pleiotropy (broadly construed so that effects are not necessarily confined to the same individual). A number of theoretical investigations considered the case where a pair of alleles at a locus influences two fitness components and derived the conditions giving rise to stable polymorphism under various assumptions about the mode of trait-interaction. Strikingly, many of these analyses concluded that