Gene knockouts often fail to reveal phenotypes, suggesting that biological systems are laden with compensation mechanisms, which might involve functional redundancy between duplicated genes or between alternative pathways and networks. In the January 2
Analysis of fitness measurements for nearly all single-gene deletion mutants in the yeast
In addition, deleting the gene copy that is most highly expressed had the greatest effect on fitness. Functional compensation between duplicate genes may account for a quarter of gene deletions without phenotypes.