Month: September 2022

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

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

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

TOOL REWIRING. "Some of these “experiments” were successful, producing the animal body plans that we see today. Each of the many diverse body plans would have been formed by a distinct regulatory network, formed by roughly the same set of regulatory genes acting in different combinations and regulated by a different set of developmental enhancers." https://lnkd.in/dTKCkih View in LinkedIn

LOSS OF TOOL PLASTICITY. "Due to developmental constraint, these core GRNs have been highly conserved since the Cambrian. Disruption of these core developmental networks is generally catastrophic, and so, once established, they are very difficult to modify and change (i.e., have low “evolvability”)." (GRNs = gene regulatory networks). https://lnkd.in/dTKCkih View in LinkedIn

SLOW EVOLUTION. "CNEs are slowly evolving but not entirely frozen sequences and in some cases changes in CNEs might reflect tinkering with developmental GRNs." (GRNs = gene regulatory networks; CNEs = conserved non-coding elements). https://lnkd.in/dTKCkih View in LinkedIn

POST CAMBRIAN TOOLKIT. "The stability of animal body plans and the underlying GRNs after the Cambrian period have resulted in many of these cis-regulatory elements being maintained ever since as sequences that evolve very slowly and in parallel in different animal groups." (GRNs = gene regulatory networks). https://lnkd.in/dTKCkih View in LinkedIn

FROM EXPLOSION TO TINKERING. "Once a large range of morphologies were explored, the major animal forms were fixed and subsequent diversification occurred through finer tinkering and re-use, mainly affecting later development." https://lnkd.in/dTKCkih View in LinkedIn

TINKERING FOR A BILLION YEARS. "Many of the regulatory genes in butterflies, giraffes and squid, for example, are similar, having been inherited from their last common ancestor, the protostome–deuterostome ancestor, which lived at least half a billion years ago. Thus the striking changes in body plans have been accompanied by relatively modest tinkering with the machinery of early development of that long-extinct precursor." https://lnkd.in/dx4KvtT View in LinkedIn

HOX GENES. "Many different classes of regulatory genes share a common DNA sequence known as the homeobox, which predates the origin of animals. In complex organisms the Hox cluster specifies the developmental fate of individual regions within the body, and usually the genes are activated and expressed in the body in the same order as their position in the cluster." https://lnkd.in/dx4KvtT View in LinkedIn