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In developmental biology, left-right asymmetry (LR asymmetry) is the process in early embryonic development that breaks the normal symmetry in the bilateral embryo.In vertebrates, left-right asymmetry is established early in development at a structure called the left-right organizer (the name of which varies between species) and leads to activation of different signalling pathways on the left ...
Fluctuating asymmetry (FA) is often considered to be the product of developmental stress and instability, caused by both genetic and environmental stressors. The notion that FA is a result of genetic and environmental factors is supported by Waddington's notion of canalisation, which implies that FA is a measure of the genome's ability to successfully buffer development to achieve a normal ...
Asymmetry is the absence of, or a violation of, symmetry (the property of an object being invariant to a transformation, such as reflection). [1] Symmetry is an important property of both physical and abstract systems and it may be displayed in precise terms or in more aesthetic terms. [ 2 ]
Asymmetric cell division is integral during development. In spiralia, the first cleavage can be either symmetric or asymmetric, as shown in the left panel. Asymmetry can be accomplished through simple unequal segregation of cell fate determinants across a single plane, through sequestration of cell fate determinants in a polar lobe which is ...
Symmetry breaking occurs at several different levels in order to generate the anatomical asymmetry which we observe. These levels include asymmetric gene expression, protein expression, and activity of cells. For example, left–right asymmetry in mammals has been investigated extensively in the embryos of mice. Such studies have led to support ...
Asymmetry in the Sylvian fissure (also known as the lateral sulcus), which separates the frontal and parietal lobes from the temporal lobe, was one of the first incongruencies to be discovered. Its anatomical variances are related to the size and location of two areas of the human brain that are important for language processing, Broca's area ...
Gesell found asymmetric development to be common in children. [11] In motor behaviors, this can be seen in an infant’s tonic neck reflex, where babies prefer to lie with their heads turned to one side and extend their arm to the same side which the head is turned while flexing the other arm behind their head. It is a reflex where the infant ...
Chirality is also seen in the study of facial asymmetry and is known as aurofacial asymmetry. [35] Schema of the development of the axial twist in vertebrates. According to the Axial Twist theory, vertebrate animals develop into a left-handed chirality.