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Bacteria exhibit three different types of asymmetry: conditional asymmetry, reproductive asymmetry, and morphological asymmetry. [2]Conditional asymmetry is well defined in the case of endospore formation, which is triggered by stressful environmental conditions such as increased heat, pH change, and nutrient depletion.
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]
The first one describes a bias and an asymmetric mutational pressure on each DNA strand during replication and transcription. [4] [11] Due to the asymmetric nature of the replication process, an unequal mutational frequency and DNA repair efficiency during the replication process can introduce more mutations in one strand as compared to the ...
Cover of the first edition. Biology Today is a college-level biology textbook that went through three editions in 1972, 1975, and 1980. The first edition, published by Communications Research Machines, Inc. (CRM) and written by a small editorial team and large set of prominent "contributing consultants", is notable for its lavish illustrations and its humanistic approach.
An asymmetric cell division produces two daughter cells with different cellular fates. This is in contrast to symmetric cell divisions which give rise to daughter cells of equivalent fates. Notably, stem cells divide asymmetrically to give rise to two distinct daughter cells: one copy of the original stem cell as well as a second daughter ...
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 ...
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 ...
Nonrandom X-inactivation leads to skewed X-inactivation. Nonrandom X-inactivation can be caused by chance or directed by genes. If the initial pool of cells in which X-inactivation occurs is small, chance can cause skewing to occur in some individuals by causing a bigger proportion of the initial cell pool to inactivate one X chromosome.