[1] [2] These chromosomes display a complex three-dimensional structure, which plays a significant role in transcriptional regulation . (wikipedia.org)
The mechanisms effecting establishment, maintenance, and modification of that specific physical conformation of CHROMATIN determining the transcriptional accessibility or inaccessibility of the DNA. (lookformedical.com)
EcDNA2
Extrachromosomal DNA (abbreviated ecDNA) is any DNA that is found off the chromosomes, either inside or outside the nucleus of a cell. (wikipedia.org)
Although extrachromosomal circular DNA (eccDNA) is found in normal eukaryotic cells, extrachromosomal DNA (ecDNA) is a distinct entity that has been identified in the nuclei of cancer cells and has been shown to carry many copies of driver oncogenes. (wikipedia.org)
In addition to DNA found outside the nucleus in cells, infection by viral genomes also provides an example of extrachromosomal DNA. (wikipedia.org)
Although prokaryotic organisms do not possess a membrane-bound nucleus like eukaryotes, they do contain a nucleoid region in which the main chromosome is found. (wikipedia.org)
Segregation2
The maintenance of a single centromere per chromosome is critical for establishing bipolar microtubule attachments to the mitotic spindle and achieving high-fidelity genome segregation 17 . (nature.com)
This family of proteins includes a wide variety of classes, including CYCLIN-DEPENDENT KINASES, mitogen-activated kinases, CYCLINS, and PHOSPHOPROTEIN PHOSPHATASES as well as their putative substrates such as chromatin-associated proteins, CYTOSKELETAL PROTEINS, and TRANSCRIPTION FACTORS. (lookformedical.com)
As each chromosome contains a single centromere, it remains unclear how acentric fragments derived from shattered chromosomes are inherited between daughter cells during mitosis 6 . (nature.com)
Here we tracked micronucleated chromosomes with live-cell imaging and show that acentric fragments cluster in close spatial proximity throughout mitosis for asymmetric inheritance by a single daughter cell. (nature.com)
Here we show that pulverized chromosomes from micronuclei spatially cluster throughout mitosis and identify the CIP2A-TOPBP1 complex as an essential regulator of this process. (nature.com)
All chromosomes normally appear as an amorphous blob under the microscope and only take on a well-defined shape during mitosis. (iiab.me)
It is entirely coincidental that the Y chromosome, during mitosis, has two very short branches which can look merged under the microscope and appear as the descender of a Y-shape. (iiab.me)
Heredity2
In his famous textbook The Cell in Development and Heredity , Wilson linked together the independent work of Boveri and Sutton (both around 1902) by naming the chromosome theory of inheritance the Boveri-Sutton chromosome theory (the names are sometimes reversed). (wikipedia.org)
[14] These observations represent an important prelude to Mendel's theory of particulate inheritance insofar as it features a transition of heredity from its status as myth to that of a scientific discipline, by providing a fundamental theoretical basis for genetics in the twentieth century. (alquds.edu)
Organism2
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. (wikipedia.org)
The X and Y chromosomes are thought to have evolved from a pair of identical chromosomes, [11] [12] termed autosomes, when an ancestral animal developed an allelic variation, a so-called "sex locus" - simply possessing this allele caused the organism to be male. (iiab.me)
Heterochromatin1
Long before the identification of its molecular nature, it was recognized that chromatin exists in two main states: the densely stained heterochromatin contrasting with euchromatin ( Heitz, 1928 ). (biologists.com)
Genes4
[7] All Y-linked genes are expressed and (apart from duplicated genes) hemizygous (present on only one chromosome) except in the cases of aneuploidy such as XYY syndrome or XXYY syndrome . (iiab.me)
The Y chromosomes of humans and other mammals also contain other genes needed for normal sperm production. (iiab.me)
Over time, genes that were beneficial for males and harmful to (or had no effect on) females either developed on the Y chromosome or were acquired through the process of translocation . (iiab.me)
Trait inheritance and molecular inheritance mechanisms of genes are still primary principles of genetics in the 21st century, but modern genetics has expanded to study the function and behavior of genes. (alquds.edu)
Genome1
With a 30% difference between humans and chimpanzees, the Y chromosome is one of the fastest-evolving parts of the human genome . (iiab.me)
Genetic material1
These studies implicate a potential mechanism suppressing the loss of genetic material after chromosome pulverization, although how distinct patterns of rearrangements arise in cancer and germline disorders remains unclear. (nature.com)
Aneuploidy2
Aneuploidy is an abnormality in the number of chromosomes in a cell due to loss or duplication. (genome.gov)
Mitotic clustering facilitates the reassembly of acentric fragments into rearranged chromosomes lacking the extensive DNA copy-number losses that are characteristic of canonical chromothripsis. (nature.com)
The stochastic inheritance of chromosome fragments by both newly formed daughter cells could in part contribute to the alternating DNA copy-number states that are characteristic of chromothripsis 2 . (nature.com)
Autosomal dominant is a pattern of inheritance characteristic of some genetic disorders. (genome.gov)
Autosomal recessive is a pattern of inheritance characteristic of some genetic disorders. (genome.gov)
Blending inheritance leads to the averaging out of every characteristic, which as the engineer Fleeming Jenkin pointed out, makes evolution by natural selection impossible. (alquds.edu)
Base pairs2
The DNA in the human Y chromosome is composed of about 59 million base pairs. (iiab.me)
The repeating structural units of chromatin, each consisting of approximately 200 base pairs of DNA wound around a protein core. (lookformedical.com)
Independently2
Bacterial plasmids are typically short sequences, consisting of 1 to a few hundred kilobase (kb) segments, and contain an origin of replication which allows the plasmid to replicate independently of the bacterial chromosome. (wikipedia.org)
Walter Sutton (left) and Theodor Boveri (right) independently developed the chromosome theory of inheritance in 1902. (wikipedia.org)
Humans1
The Y chromosome is one of two sex chromosomes ( allosomes ) in mammals, including humans , and many other animals. (iiab.me)
Patterns3
Thus, distinct patterns of chromothripsis can be explained by the spatial clustering of pulverized chromosomes from micronuclei. (nature.com)
Mitotic clustering drives the unequal inheritance of acentric fragments by a single daughter cell, providing an explanation for the origins of distinct patterns of chromothripsis found across diverse cancer types and congenital disorders. (nature.com)
Mendel studied "trait inheritance", patterns in the way traits are handed down from parents to offspring over time. (alquds.edu)
Structures1
Otto Bütschli was the first scientist to recognize the structures now known as chromosomes. (wikipedia.org)
Diseases1
Multiple forms of extrachromosomal DNA exist, and, while some of these serve important biological functions, they can also play a role in diseases such as cancer. (wikipedia.org)
Main1
Mitochondrial DNA is a main source of this extrachromosomal DNA in eukaryotes. (wikipedia.org)
Cell division2
Others use the concept in a narrower sense, to refer to the individualized portions of chromatin during cell division, visible under light microscopy due to high condensation. (wikipedia.org)
ecDNAs lack centromeres, and are consequently subject to random inheritance during cell division, driving intratumoral genetic heterogeneity 6 . (nature.com)
Copies1
[4] Before this happens, each chromosome is duplicated ( S phase ), and both copies are joined by a centromere , resulting either in an X-shaped structure (pictured above), if the centromere is located equatorially, or a two-arm structure, if the centromere is located distally. (wikipedia.org)
Exists1
Extrachromosomal DNA exists in prokaryotes outside the nucleoid region as circular or linear plasmids. (wikipedia.org)
Found2
In prokaryotes, nonviral extrachromosomal DNA is primarily found in plasmids, whereas, in eukaryotes extrachromosomal DNA is primarily found in organelles. (wikipedia.org)
Extrachromosomal DNA in the cytoplasm has been found to be structurally different from nuclear DNA. (wikipedia.org)
Term1
[9] The term was coined by the German anatomist Heinrich Wilhelm Waldeyer , [10] referring to the term chromatin , which was introduced by Walther Flemming . (wikipedia.org)
Highly1
During metaphase the X-shaped structure is called a metaphase chromosome, which is highly condensed and thus easiest to distinguish and study. (wikipedia.org)
Rules1
Aided by the rediscovery at the start of the 1900s of Gregor Mendel 's earlier work, Boveri was able to point out the connection between the rules of inheritance and the behaviour of the chromosomes. (wikipedia.org)
Sexual reproduction1
During dynamic developmental events, such as sexual reproduction, we propose that dramatic and rapid reconfiguration of source-sink relationships modifies chromatin states. (biologists.com)
Complex1
Mechanistically, the CIP2A-TOPBP1 complex prematurely associates with DNA lesions within ruptured micronuclei during interphase, which poises pulverized chromosomes for clustering upon mitotic entry. (nature.com)
Remains1
The portion of chromosome material that remains condensed and is transcriptionally inactive during INTERPHASE. (lookformedical.com)
Identify1
Extrachromosomal DNA is often used in research into replication because it is easy to identify and isolate. (wikipedia.org)
Study1
The Y chromosome was identified as a sex-determining chromosome by Nettie Stevens at Bryn Mawr College in 1905 during a study of the mealworm Tenebrio molitor . (iiab.me)