Genomic patterns of pleiotropy and the evolution of complexity

摘要: Pleiotropy refers to the phenomenon of a single mutation or gene affecting multiple distinct phenotypic traits and has broad implications in many areas biology. Due its central importance, pleiotropy also been extensively modeled, albeit with virtually no empirical basis. Analyzing phenotypes large numbers yeast, nematode, mouse mutants, we here describe genomic patterns pleiotropy. We show that fraction altered appreciably by deletion is minute for most genes gene–trait relationship highly modular. The standardized size effect on trait approximately normally distributed variable SDs different genes, which gives rise surprising observation larger per-trait more traits. This scaling property counteracts pleiotropy-associated reduction adaptation rate (i.e., “cost complexity”) nonlinear fashion, resulting highest organisms intermediate complexity rather than low complexity. Intriguingly, observed exponent falls narrow range maximizes optimal Together, genome-wide observations overall pleiotropy, high modularity, effects from higher necessitate major revisions theoretical models suggest not only allowed but promoted evolution