How Fisherian runaway halts: Genomic architecture determines the long-term evolutionary consequences of sexual selection.

Sexual selection, which drives the evolution of extravagant sexual displays, also necessitates biased mate preferences for the process to occur. In 1930, Ronald Fisher postulated that such preferences could initiate a self-reinforcing cycle of evolutionary change, or "runaway," where mate choice exerts sexual selection on the displays themselves and links them genetically to mate preferences.

Mathematical models have supported the plausibility of this theory; however, several assumptions are idealized, leaving open questions about how and why runaway processes come to an end in real-world populations. Investigating these gaps, researchers have employed two complementary methods: reviewing existing theories to categorize mechanisms that terminate runaway into four groups, depending on which idealized assumptions of Lande's (1981) classic model are breached during runaway evolution; and conducting individual-based simulations that vary the genetic architecture of sexual displays, from conventional additive to omnigenic inheritance models.

The findings indicate that the genetic architecture of sexual displays plays a crucial role in determining how runaway processes cease, thereby influencing the long-term evolutionary consequences of sexual selection.