Ancestral reconstruction of a signaling pathway reveals the mutations responsible for producing specificity of the two paralogous pathways produced by a duplication event.

Ancient animal Dicer used its helicase domain to couple the detection of foreign double-stranded RNA to efficient ATP hydrolysis and antiviral defense, but this function declined before the advent of deuterostomes and vertebrates.

Mammals evolved an invasive placenta early in the origins of pregnancy.

Tight regulation of a central developmental kinase cascade evolved through two key mutations.

The behavioral repertoires from six species of flies are measured, and a statistical approach is developed to predict co-evolving behaviors, providing a potential framework for exploring behavioral evolution.

Phylogenetic and biochemical analysis reveals crucial role of two substitutions in the α–crystallin domain for development of new functionality of IbpA chaperone after the loss of paralogous IbpB in Erwiniaceae.

Reconstructing ancestral enzymes has revealed that a switch in kinase substrate preference evolved via an expanded specificity intermediate that is tolerated in vivo, thus providing a path for kinase diversification.

Pulsed-labeling hydrogen exchange on the ribonuclease H family show that the major folding intermediate is conserved over three billion years of evolution, but the path leading to this intermediate varies.

Life is constrained in its sampling of protein sequence space to catalyze one of the most energetically challenging biochemical reactions.

The genomes of animal progenitors evolved as mosaics of old, new, rearranged, and repurposed protein domains, genes and pathways and paved the way for the origin and evolution of animals.