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Segmentation in biology is the division of some animal and plant body plans into a linear series of repetitive segments that may or may not be interconnected to each other. This article focuses on the segmentation of animal body plans, specifically using the examples of the taxa Arthropoda , Chordata , and Annelida .
The gap genes are part of a larger family called the segmentation genes. These genes establish the segmented body plan of the embryo along the anterior-posterior axis. The segmentation genes specify 14 parasegments that are closely related to the final anatomical segments. The gap genes are the first layer of a hierarchical cascade of the ...
Modern groups of animals can be grouped by the arrangement of their body structures, so are said to possess different body plans. A body plan, Bauplan (pl. German: Baupläne), or ground plan is a set of morphological features common to many members of a phylum of animals. [1] The vertebrates share one body plan, while invertebrates have many.
Ed Lewis, Christiane Nüsslein-Volhard and Eric F. Wieschaus identified and classified 15 genes of key importance in determining the body plan and the formation of body segments of the fruit fly D. melanogaster in 1980. [60] For their work, Lewis, Nüsslein-Volhard, and Wieschaus were awarded the Nobel Prize in Physiology or Medicine in 1995. [61]
The nervous system segmentation confers several developmental advantages to the vertebrate body as humans possess a body plan that is bilaterally segmented at the nervous system level. The segmentation is involved at all levels of the human nervous system with increasing level of complexity in the innervation from the brain to limbs. [1]
The development of the somites depends on a clock mechanism as described by the clock and wavefront model. In one description of the model, oscillating Notch and Wnt signals provide the clock. The wave is a gradient of the fibroblast growth factor protein that is rostral to caudal (nose to tail gradient). Somites form one after the other down ...
Earthworms are a classic example of biological homonymous metamery – the property of repeating body segments with distinct regions. In biology, metamerism is the phenomenon of having a linear series of body segments fundamentally similar in structure, though not all such structures are entirely alike in any single life form because some of them perform special functions. [1]
Differences in deployment of toolkit genes affect the body plan and the number, identity, and pattern of body parts. Most toolkit genes are parts of signalling pathways : they encode transcription factors , cell adhesion proteins, cell surface receptor proteins and signalling ligands that bind to them, and secreted morphogens that diffuse ...