Scaffold meaning in molecular biology4/24/2023 ![]() ![]() It has been further developed in collaboration with Andrew Black and Pierrick Bourrat. The idea, in general form, we refer to as “ecological scaffolding”. One potential solution comes from recognising the role that the environment can play in exogenously imposing Darwinian properties on otherwise “unwitting” particles. This leads to a very particular dilemma, namely, the need to explain the evolution of Darwinian properties, in non-Darwinian entities (e.g., the first collective), by non-Darwinian means (it is not possible to invoke the thing one wants to explain (the evolution or reproduction) as the cause of its own evolution). The collective that results grows by virtue of the reproductive capacity of individual cells, but in the absence of a means of collective level reproduction, the collective – like soma – is an evolutionary dead end. Consider a nascent multicellular collective that arises from a mutation that causes cell adhesion. With exception of the transition from non-life to life, these properties manifest at the lower level, but their existence at, for example, the level of the individual cell, does not mean that these same properties automatically appear at the level of collectives of cells. The following is adapted from Rainey et al (2017): A central issue for each transition concerns the emergence of Darwinian properties of variation, reproduction and heredity without which the process of evolution by natural selection cannot occur. Such transitions include the evolution of networks of self-replicating chemistries (from single autocatalytic reactions), the evolution of chromosomes (from once separate genes), evolution of the eukaryotic cell (from ancestral archaebacterial and eubacterial cells), the evolution of sex (from asexual types), the evolution of multicellularity (from single cells) and evolution of eusociality (from asocial types). As John Maynard Smith and Eros Szathmary in their highly influential book realised, the rise of biological complexity has been marked by a small number of events in which self-replicating entities, by various means, align reproductive fates and come to replicate as a single collective.
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