| Abstract | Morphogenesis is achieved through volumetric growth of tissue at a rate varying over space and time. The volumetric growth rate of each piece of tissue reflects the behaviors of constituent cells, such as cell proliferation, cell death, cell growth and deformation. Hence clarifying the spatio-temporal pattern of volumetric growth accurately is a key to bridge between cell behaviors and morphogenesis of a tissue or an organ. Fate map data specifying the correspondence of cell positions between different stages provide potentially important information on the volumetric growth rate. However, their resolution on space and time are often limited, and they include unavoidable noises. In this paper, we propose a new method to estimate the spatio-temporal pattern of volumetric growth rate from fate map data. The method complements the data defects by using a mathematical model for cell trajectory dynamics and a statistical method (AIC). We apply the method to fate map data along the proximo-distal axis on chick wing development, and find that the volumetric growth pattern is biphasic: it is spatially uniform in earlier stages (until stage 23), but in later stages the volumetric growth occurs about four times as fast as in the distal region (within about 100 from the limb tip) than in the proximal region. The quantitative volumetric growth pattern will be a good indicator when we discuss the morphological anomalies of mutants and between-species differences of development, and in addition, when we quantitatively evaluate results obtained from mathematical model to describe organ growth and deformation. |
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