Increasingly, historians of biology are paying attention to the various ‘personal syntheses’ achieved in the early to mid-twentieth century. This period, which has traditionally been viewed as one of synthesis, is becoming one of many syntheses, as we ask how individual evolutionists brought together and negotiated the assorted scientific, conceptual, practical and other resources at their disposal. The present paper explores a case in which these two perspectives intersect.
The synthesis in evolutionary studies, traditionally conceived, amounted to a reconciliation of Darwin’s theory of natural selection with the burgeoning field of Mendelian genetics. In accounts of this synthesis, Ronald Aylmer Fisher (1890-1962) routinely takes centre-stage. His celebrated paper of 1918 represents for many the first successful attempt to mathematically reconcile Darwinism and Mendelism. At other times, historians speak of this theoretical synthesis as the achievement, somewhat paradoxically, of a whole community of researchers. This paper, then, grapples with questions as to the nature of the evolutionary synthesis, and to whom (if anyone) it belonged.
By way of disentangling the above difficulty, and with reference to correspondence and new archival material, this paper follows Fisher through the formative years between his student days on the Mathematical Tripos at Cambridge in the 1910s, and the publication in 1930 of his lastingly influential Genetical Theory of Natural Selection. In particular, I ask: how did Fisher synthesise Darwinian selectionism and Mendelian genetics? From which resources did he gain his knowledge of each? Why did he set himself this synthesising task?

Motoo Kimura began the neutralist-selectionist divide when, in 1969, he hypothesized that most substitutions of amino acids in proteins are selectively neutral and developed the neutral theory of molecular evolution. While neutralism began as an empirical claim, it transformed into a methodology investigating evolutionary patterns ignoring selection. Where selectionists look first for the effects of natural selection, neutralists look first for the effects of drift, migration, and mutations. This methodological divide expanded first to paleobiology and then community ecology, and later beyond biology to economics and linguistics. Biologists, historians, and philosophers of science understand this divide well in evolution, partially in paleobiology, and barely in community ecology. But they have not noticed it beyond biology, and have not appreciated that it has the general methodological divide it is. Anywhere scientists investigate abundance patterns and favor selection explanations, neutralists seem likely to appear. Why is this? In this talk I will show that epistemic, sociological, and historical factors are all responsible. Data for abundance patterns is poor for most natural systems, and it is difficult to establish that selection is operating. This gives rise alternatively to groups of scientists who double-down on finding selection and who ignore selection. These episodes are not independent, however. For example, Stephen Jay Gould migrated between evolution and paleobiology and Daniel Simberloff between community ecology and paleobiology, each carrying tools and methods along. Analyzing this divide with these factors will enrich our understanding of why biologists use the methodologies that they do.

Allostery describes the process whereby ligand binding at one site on a protein transmits an effect to another distal site. Ever since its discovery in 1961, allostery has remained an important topic within structural biology because of its role in cell regulation. However, the concept has changed drastically since Jacques Monod and his colleagues first characterized it. This paper aims to recount the conceptual evolution of allostery over the past 50 years. I argue that the concept has evolved in three stages. First, from the late 1950s to the  mid-1960s, allostery was a population-level phenomenon, closely tied to biochemistry and heterodox enzyme kinetics. Then, starting in the mid-1960s and extending to the mid-2000s, allostery became a feature of individual protein molecules with special structural and conformational properties. The final stage in this conceptual evolution, which introduced the ‘ensemble nature of allostery’, began in the mid-2000s (Motlagh et al. 2014). Creager and Gaudilliere (1996) have offered an explanation for the first historical transition based on the complex interplay between theory and experiment, and it is the primary aim of this paper to characterize the second transition and offer an explanation for it. I aim to show that the driving forces behind the conceptual shift from the structural-mechanistic view to the ensemble view were twofold: (1) the mounting body of anomalies that could not be explained by any of the structural-mechanistic models of allostery and (2) the increasing recognition that protein dynamics play an important role in protein structure and function.