Month: September 2022

SACRIFICIAL INTERMEDIATE HOST. "A type of parasitic flatworm targets cockles in New Zealand, driving the marine mollusks to the surfaces of muddy bottoms in shallow waters. There, oystercatcher birds snap the cockles up and eat them, flatworms and all. The shorebirds serve as the final hosts in the flatworms' complex life cycle." http://news.nationalgeographic.com/news/2005/09/0901_050901_wormparasite.html View in LinkedIn

SO ENDS this first weekend on parasite-host relations, an ancient and wine widespread phenomenon in nature that ranges from true parasitism to mutualism. This does not cover the range of microbial and viral parasitism. These examples serve to illustrate the deeply sophisticated ways that a body may be hacked by another creature. View in LinkedIn

RNA DEFINED BY GAME THEORY. "Social membership is not considered. Nor is the emergence of complex behavior or phenotype crucial. Interactions within and between networks simply must emerge from individual fittest type origins as suggested in former quasispecies concepts. There are no group behavioral issues or principles that must be adhered to. The collective has no group fitness even though it can show emergent features." https://lnkd.in/eUYvi8e View in LinkedIn

THE GREY ZONE. "The core issue is thus to specify how “agents” emerge from chemicals (ribozymes) to form identity (such as for replicators) and then form groups that learn membership. For all extant life, these agents must have initially been RNA stem loops. Single RNA stem-loop generation occurs by physical chemical properties solely as demonstrated by natural and randomized RNA experiments." https://lnkd.in/eUYvi8e View in LinkedIn

STEP FROM THE GREY ZONE. "If stem-loop consortia build complex consortia they initiate social interactions not present in a pure chemical world. The emergence of identity (self vs. nonself) is a crucial step from single RNA stem loops to RNA consortia; maybe the crucial step from inanimate world to life?" https://lnkd.in/eUYvi8e View in LinkedIn

UNIVERSAL TEMPLATE STRUCTURES. "Natural selection is not required to explain universal compositional patterns in rRNA secondary structure categories. We have encountered an unexpected property of rRNA secondary structures that may generalize to all RNAs. Analysis of 8892 ribosomal RNA sequences and structures from a wide range of species revealed unexpected universal compositional trends." https://lnkd.in/erj2nzZ View in LinkedIn

UNEXPECTED PROPERTIES. "First, different categories of rRNA secondary structure (stems, loops, bulges, and junctions) have distinct, characteristic base compositions. Second, the observed patterns of variation are similar among sequences from large and small rRNA subunits and all domains of life, despite extensive evolutionary divergence. https://lnkd.in/erj2nzZ View in LinkedIn

EVOLUTIONARY DIVERGENCE OF LOOPS. "Surprisingly, these differences do not seem to be related to selection for different compositions in different structural categories, but rather relate to the overall composition of the molecule: Randomized RNAs with no evolutionary history show the same structure-dependent compositional biases as rRNAs" https://lnkd.in/erj2nzZ View in LinkedIn

SURPRISE FINDING. "The three domains of life diverged billions of years ago and, although the rRNA molecule is conserved for function in the different domains, the nonfunctional parts presumably varied independently in each lineage. Since there is no known sequence homology between the two ribosomal subunits, these subunits have no apparent shared ancestry. It is therefore surprising to see the same patterns of variation across all domains and both subunits." https://lnkd.in/erj2nzZ View in LinkedIn

RIBOSOMAL RNA. "There are striking similarities in the composition of the different structural categories across both ribosomal subunits and the three domains of life, despite much evolutionary divergence." https://lnkd.in/erj2nzZ View in LinkedIn