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TOOL COMPLEXIFICATION. "In an ancestral metazoan, this parts list must have been employed in relatively simple GRNs, controlling the development of an ancestral body plan. During early animal evolution there must have been a period of rapid experimentation involving the re-wiring of this parts list in many different combinations." (GRNs = gene regulatory networks). https://lnkd.in/dTKCkih View in LinkedIn

OLD DRIVERS. "Historically, cultural evolution occurred through migration. Migration happens as a result of war, geographical changes or survival requirements and demands. War affected the cultures morals, and regions (if they were dominated etc.) Regional domination could imply control over the population, causing the citizens to move.” https://lnkd.in/dsKGhcp View in LinkedIn

SIMILAR TOOLS. "A central conclusion from decades of developmental genetics is that the same regulatory genes control development across diverse animal groups. That is, the same basic “parts list” is re-deployed in the core of developmental programs of diverse animals, and it is the alternative regulatory connections between these genes that must explain most of the alternative morphologies of animals." https://lnkd.in/dTKCkih View in LinkedIn

AN ENORMOUS CULTURAL EXPERIMENT is taking share before our eyes. Our youth have digitized childhoods, locked into social media in a way never seen before. The next generation will have an entirely different relationship to the internet and the cybernetic world, and likely be early adopters of new virtual technology. View in LinkedIn

AMPLIFIED OPTIONS. "Gene duplication itself is widely considered to facilitate evolution. The redundancy that arises immediately following duplication is generally thought to allow for beneficial mutations to accumulate and new functions to arise. Thus, the increase in parts (regulatory genes) and the resulting explosion in the ways the parts could be put together probably opened up new possibilities of forms that, under permitting environmental and ecological conditions, could be attained." https://lnkd.in/dTKCkih View in LinkedIn

TOOLKIT AMPLIFICATION MATHS. "To illustrate the point, a network of 2 genes that can activate, repress, or do nothing to each other or themselves, has 81 possible topologies, while a network of 3 such genes has 19,683 possible topologies (number of topologies = 3(n)(2), where there are n2 interactions between pairs of genes and each interaction can be positive, negative, or neither of the two)." https://lnkd.in/dTKCkih View in LinkedIn

EXPANDED GENE TOOLKIT. "At least part of the potential for developmental evolution during the Cambrian may therefore simply stem from the expansion of the repertoire of regulatory genes in the metazoan ancestor. An increase in regulatory proteins (that can act alone or in combinations) translates into a much bigger increase in possible regulatory network configurations (“topologies”)." https://lnkd.in/dTKCkih View in LinkedIn

PRIOR GENE EXPANSION. "Classes of transcription factors involved in animal development, such as HOX, SOX, POU, F-box, and T-box, emerged most likely before the divergence of the different bilaterian animals but after the split of the basal choanoflagellate lineage from the bilaterian lineage. These metazoan transcription factor classes greatly expanded through duplication in the bilaterian ancestor, just before the Cambrian “explosion”." https://lnkd.in/dTKCkih View in LinkedIn

BILATERALISM. "Close to the period of animal diversification prior to the Cambrian, the major classes of bilaterian regulatory genes greatly expanded." https://lnkd.in/dTKCkih View in LinkedIn

FRAGMENT FROM NATURE continues from last weekend and concludes on the theme of the Cambrian explosion, this time focusing on some of the genetic findings that can help fill in the missing fossil record. View in LinkedIn