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EARLIEST ASYMMETRY. "Over the past few decades, the C. elegans embryo has become a premiere system for studying cellular symmetry breaking in a developmental context. During C. elegans development, nearly every division produces daughter cells with different developmental trajectories." https://lnkd.in/dAxynvD View in LinkedIn

THIRD FINDING. "Declining frequencies of spontaneous asymmetry reversal throughout vertebrate evolution suggest that heart development has become more canalized." https://lnkd.in/dAEUFWY View in LinkedIn

SECOND FINDING. "The molecular pathway directing hearts leftward—the nodal cascade—varies considerably among vertebrates (homology of form does not require homology of development) and was possibly co-opted from a preexisting asymmetrical chordate organ system." https://lnkd.in/dAEUFWY View in LinkedIn

FIRST FINDING. "Directional asymmetry, an evolutionary novelty, arose from nonheritable origins almost as often as from mutations, implying that genetic assimilation (“phenotype precedes genotype”) is a common mode of evolution." https://lnkd.in/dAEUFWY View in LinkedIn

CUE CANDIDATES. "These observations suggest the attractive possibility that the threshold for triggering a self-amplifying asymmetry is associated with the formation kinetics of local Rho-depleted and/or Par-2-rich/myosin inhibitory domains. Simple mathematical analyses show that such feedback loops could endow the cortex with a threshold response." https://lnkd.in/dAxynvD View in LinkedIn

SURPRISE FINDINGS. "Phylogenetic analyses of asymmetry variation, inheritance, and molecular mechanisms reveal unexpected insights into how development evolves." Especially applied to the symmetry of the heart. https://lnkd.in/dAEUFWY View in LinkedIn

CUE THRESHOLD. "There is a threshold level of inhibition that the cue must exceed to trigger symmetry breaking. This could either be a threshold in the inhibition domain size, the duration of inhibition, or both." https://lnkd.in/dAxynvD View in LinkedIn

LEFT-RIGHT ASYMMETRY. "Because of its simplicity, the binary-switch nature of left-right asymmetry permits meaningful comparisons among many different organisms." https://lnkd.in/dAEUFWY View in LinkedIn

CUES AND NO CUES. "Some symmetry-breaking systems require a polarizing cue. Others can spontaneously break symmetry in the absence of any cues, often by amplifying local stochastic fluctuations in the concentrations of participating molecules. In these cases, polarizing cues “choose” the axis of symmetry breaking." https://lnkd.in/dAxynvD View in LinkedIn

FRAGMENT FROM NATURE deals with symmetry and symmetry breaking in animal body design. Symmetry is a common theme that threads through biology, physics and chemistry. It seems fundamental to how the universe is configured. In biology, the issue of symmetry starts at the first cell division of the egg, and does not stop thereafter. It seems that symmetry breaking and chirality is embedded in the very geometry of shape. View in LinkedIn