However, breakthroughs regarding the identity of the molecules comprising the Clock and the Wavefront were only made 20 years later. According to this model, somite size and number are jointly determined by the period of the clock’s oscillations and the speed of the moving wavefront ( Cooke and Zeeman, 1976 Oates et al., 2012).

Together, these two components would translate temporal information into a spatial pattern. Exposure of a clock-induced cell population to the wavefront signal would promote a rapid change in cell properties, leading to the formation of a somite. In their Clock and Wavefront model ( Cooke and Zeeman, 1976), the authors proposed the existence of two players: a molecular oscillator ( clock), responsible for the rhythmic generation of a cell responsive state, and a maturation wavefront, moving slowly in an anterior-to-posterior direction. In 1976, Cooke and Zeeman proposed a theoretical model that aimed to explain the formation of periodic structures during vertebrate development. This is characteristic of all vertebrates, although the pace at which somites are formed varies among species ( Table 1). Most importantly to the subject of this review, somite pairs are formed sequentially, over time, while the embryonic body is elongating in an A-P direction. In fact, somites not only give rise to the axial skeleton and skeletal musculature, but also impose the segmented organization of the peripheral nervous system ( Keynes and Stern, 1988). Somites are formed in pairs from the anterior-most portion of the presomitic mesoderm (PSM), on each side of the neural tube, and they are the first morphological manifestation of the characteristic segmented structure of the adult vertebrate axial skeleton. One such process is somitogenesis, which is characterized by the periodic formation of metameric structures, the somites, along the anterior-to-posterior (A-P) axis of the early embryonic body. Vertebrate embryo development comprises several processes that are highly regulated in time. An outstanding question, however, remains unanswered: what sets the different EC paces observed in different organisms and tissues? This review aims to summarize the available knowledge regarding the pace of the EC, its regulation and experimental manipulation and to expose new questions that might help shed light on what is still to unveil. The EC is now known to be present in all vertebrate organisms studied and this mechanism was also described in limb development and stem cell differentiation. The discovery of a molecular Embryo Clock (EC) underlying the periodicity of somite formation shed light on the importance of gene expression dynamics for pattern formation. Pairs of somites flanking the neural tube are formed periodically during early development, and the molecular mechanisms in temporal control of this early patterning event have been thoroughly studied. Very simple practice mode with only one finger tap.Īre you having problems? Send email to Soon Menu in Dancing Line iOS port.Vertebrate embryo somitogenesis is the earliest morphological manifestation of the characteristic patterned structure of the adult axial skeleton.Multiple levels of increasing difficulty with their own stories.

Tap the screen to make a sharp turn, avoiding obstacles and reacting to the World changing before your eyes. Guide an ever-growing Line through a multiple of environments, listening carefully to the music. Listen to the beat and the melody, and after a short while, you will find yourself doing better and better.Ĭome on! Test your reflexes and rhythm skills! See the surprises and wonders every level holds for you. The key is to not only watch for obstacles and traps but also play to the music. Featuring different worlds of increasing difficulty, each one paints a unique picture and evokes different emotions. Dancing Line combines a fast-paced gameplay with a carefully selected soundtrack to create an experience like no other.

Dancing line clock