The show must go on about maintaining a segmented body plan.
The division of animal and plant body plans into a series of repetitive segments is called segmenting in biology.The examples of the taxa Arthropoda, Chordata, and Annelida are used in the article.Three groups form segments by using a growth zone.Different mechanisms for generating patterning are used by all three of them.Different organisms have different ways of segmenting the body.Free movement and the development of certain body parts can be allowed through the breakdown of the body plan.Specific individuals can be regenerated with it.
A difficult process to define is the segment.Many taxa have some form of serial repetition in their units but are not thought of as segments.The parts of an organisms that are referred to as being segments are the organs that were repeated, or have a body composed of self-similar units.[2]
Three types of animals are characteristic of different arthropods.The fruit fly forms segments from a field of equivalent cells.The somites are defined by the use of gene expression.Smaller blast cells budded off from larger teloblast cells are used by Annelids.[3]
Although not representative of the arthropods in general, it is the most studied.The discovery of a class of genes that are necessary for proper dispersal of the embryo was the result of early screens to identify genes involved in cuticle development.[4]
The anterior-posterior axis is defined by maternally supplied transcripts and is used to segment the embryo.The boundaries of the different segments are set by the expression pattern for gap genes.The expression pattern for the pair-rule genes is then defined.The pair-rule genes are mostly transcription factors that are expressed in stripes down the embryo's length.The expression of segment polarity genes is regulated by these transcription factors.The identities of each segment are later defined.[5]
The body wall, nervous system, kidneys, muscles, and body cavity are all part of the arthropods.Some elements.The onychophora is their sister taxon.[2]
The study of segmenting in the leech has been described as budding.Teloblast cells are stem cells that divide asymmetrically to create bandlets of blast cells.There are five different teloblast lineages with one set for each side of the midline.The N and Q lineages contribute two blast cells for each segment, while the M, O, and P only contribute one cell per segment.The number of segments within the embryo is determined by how many divisions and blast cells there are.The common evolutionary origin of arthropods and annelids can be seen in the regulation of segment.[6]