Search results
Results from the WOW.Com Content Network
The precise structure of the chromatin fiber in the cell is not known in detail. [10] This level of chromatin structure is thought to be the form of heterochromatin, which contains mostly transcriptionally silent genes. Electron microscopy studies have demonstrated that the 30 nm fiber is highly dynamic such that it unfolds into a 10 nm fiber ...
The eukaryotic genome is organized into a compact chromatin structure that allows only regulated access to DNA. The chromatin structure can be globally "open" and more transcriptionally permissive, or globally "condensed" and transcriptionally inactive. The former (euchromatin) is lightly packed and rich in genes under active transcription.
In those species, females have only one type of mtDNA (F), whereas males have F type mtDNA in their somatic cells, but M type of mtDNA (which can be as much as 30% divergent) in germline cells. [65] Paternally inherited mitochondria have additionally been reported in some insects such as fruit flies, [66] [67] honeybees, [68] and periodical ...
Some regions of chromatin are very densely packed with fibers that display a condition comparable to that of the chromosome at mitosis. Heterochromatin is generally clonally inherited; when a cell divides, the two daughter cells typically contain heterochromatin within the same regions of DNA, resulting in epigenetic inheritance. Variations ...
Chromatin contains the vast majority of the DNA in an organism, but a small amount inherited maternally can be found in the mitochondria. It is present in most cells, with a few exceptions, for example, red blood cells. Histones are responsible for the first and most basic unit of chromosome organization, the nucleosome.
Epigenetics involves changes in the phenotype that can be inherited without changing the DNA sequence. This can occur through many types of environmental interactions. [16] Regarding euchromatin, post-translational modifications of the histones can alter the structure of chromatin, resulting in altered gene expression without changing the DNA. [17]
The duplication and transmission of genetic material from one generation of cells to the next is the basis for molecular inheritance and the link between the classical and molecular pictures of genes. Organisms inherit the characteristics of their parents because the cells of the offspring contain copies of the genes in their parents' cells.
Bivalent chromatin domains are found in embryonic stem (ES) cells and play an important role in cell differentiation. When keeping an ES cell in its undifferentiated state, bivalent domains of DNA are used to silence developmental genes that would activate cell differentiation, while keeping the genes poised and ready to be activated. [3]