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Neomorphic mutations are a part of the gain-of-function mutations and are characterized by the control of new protein product synthesis. The newly synthesized gene normally contains a novel gene expression or molecular function. The result of the neomorphic mutation is the gene where the mutation occurs has a complete change in function. [57]
The cell cycle, or cell-division cycle, is the sequential series of events that take place in a cell that causes it to divide into two daughter cells. These events include the growth of the cell, duplication of its DNA ( DNA replication ) and some of its organelles , and subsequently the partitioning of its cytoplasm, chromosomes and other ...
When recombination is low, mutator alleles may still sometimes hitchhike on the success of adaptive mutations that they cause. In this case, selection can take place at the level of the lineage. [32] This may explain why mutators are often seen during experimental evolution of microbes. Mutator alleles can also evolve more easily when they only ...
Overview of chromosome duplication in the cell cycle. In cell biology, eukaryotes possess a regulatory system that ensures that DNA replication occurs only once per cell cycle. A key feature of the DNA replication mechanism in eukaryotes is that it is designed to replicate relatively large genomes rapidly and with high fidelity.
In many genetic control networks, positive feedback ensures that cells do not slip back and forth between cell cycle phases [12] Cyclin E:Cdk2 proceeds to phosphorylate Rb at all of its phosphorylation sites, also termed “hyper-phosphorylate”, which ensures complete inactivation of Rb. The hyper phosphorylation of Rb is considered the late ...
The eukaryotic cell seems to have evolved from a symbiotic community of prokaryotic cells. DNA-bearing organelles like mitochondria and chloroplasts are remnants of ancient symbiotic oxygen-breathing bacteria and cyanobacteria, respectively, where at least part of the rest of the cell may have been derived from an ancestral archaean prokaryote ...
Evolution by gene duplication is an event by which a gene or part of a gene can have two identical copies that can not be distinguished from each other. This phenomenon is understood to be an important source of novelty in evolution, providing for an expanded repertoire of molecular activities.
Cells may also temporarily or permanently leave the cell cycle and enter G 0 phase to stop dividing. This can occur when cells become overcrowded ( density-dependent inhibition ) or when they differentiate to carry out specific functions for the organism, as is the case for human heart muscle cells and neurons .