News tagged with chromosomes
Scientists are beginning to decode the complex biology of aging and are optimistic that recent advances in research may lead to treatments that can slow or even reverse degeneration and disease.
Medical research Nov 15, 2011 | 4.6 / 5 (15) | 5
In a recent study led by Uppsala University, the researchers compared the DNA of identical (monozygotic) twins of different age. They could show that structural modifications of the DNA, where large or small DNA segments ...
Genetics Feb 02, 2012 | 4.6 / 5 (15) | 0 |
(Medical Xpress)—University of Washington scientists have succeeded in removing the extra copy of chromosome 21 in cell cultures derived from a person with Down syndrome, a condition in which the body's ...
Medical research Nov 09, 2012 | 4.9 / 5 (11) | 0 |
Can the length of strands of DNA in patients with heart disease predict their life expectancy? Researchers from the Intermountain Heart Institute at Intermountain Medical Center in Salt Lake City, who studied the DNA of more ...
Medical research Mar 10, 2013 | 4.5 / 5 (10) | 18 |
A Washington State University researcher has found new evidence that the plastic additive BPA can disrupt women's reproductive systems, causing chromosome damage, miscarriages and birth defects.
Medical research Sep 24, 2012 | 4.6 / 5 (9) | 2 |
Suppressing a newly identified and characterized protein involved in regulating cell division could be a novel strategy to fight certain cancers because it stops the malignant cells from dividing and causes them to die quickly, ...
Cancer Dec 09, 2011 | 5 / 5 (8) | 0 |
Sanford-Burnham researchers discover that the extra chromosome inherited in Down syndrome impairs learning and memory because it leads to low levels of SNX27 protein in the brain.
Medical research Mar 24, 2013 | 4.4 / 5 (9) | 0 |
(Medical Xpress)—Replicative aging (also known as replicative senescence) causes mammalian cells to undergo a process of growth arrest dependent on telomeres (the shortening of repeated sequences at the ends o ...
Neuroscience Mar 27, 2013 | 4.9 / 5 (8) | 0 |
They are the Robinson Crusoes of the intracellular world -- lone chromosomes, whole and hardy, stranded outside the nucleus where their fellow chromosomes reside. Such castaways, each confined to its own "micronucleus," ...
Cancer Jan 19, 2012 | 4.7 / 5 (7) | 0 |
Scientists have successfully sequenced the genome of a baby in the womb without tapping its protective fluid sac. This non-invasive approach to obtaining the fetal genome is reported in the June 6 issue of ...
Genetics Jun 06, 2012 | 5 / 5 (6) | 0 |
(Medical Xpress)—On April 15, the Supreme Court will hear oral argument in Association for Molecular Pathology v. Myriad Genetics, a case that could answer the question, "Under what conditions, if any, ...
Genetics Apr 11, 2013 | 4.3 / 5 (6) | 16 |
The ability to anticipate future events allows us to plan and exert control over our lives, but it may also contribute to stress-related increased risk for the diseases of aging, according to a study by UCSF researchers.
Psychology & Psychiatry Feb 21, 2012 | 5 / 5 (5) | 1 |
(Medical Xpress) -- Is anxiety related to premature aging? A new study by researchers at Brigham and Women's Hospital (BWH) shows that a common form of anxiety, known as phobic anxiety, was associated with shorter telomeres ...
Medical research Jul 11, 2012 | 4.2 / 5 (6) | 2 |
Women live longer than men. Individuals can appear or feel years younger – or older – than their chronological age. Diseases can affect our aging process. When it comes to biology, our clocks clearly tick differently.
Medical research Nov 21, 2012 | 5 / 5 (5) | 0 |
Investigators have identified a human chromosome containing a specific gene associated with susceptibility to herpes simplex labialis (HSL), the common cold sore. Published in the Journal of Infectious Diseases and now av ...
Diseases, Conditions, Syndromes Oct 28, 2011 | 4.8 / 5 (5) | 0 |
A chromosome is an organized structure of DNA and protein that is found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions. The word chromosome comes from the Greek χρῶμα (chroma, color) and σῶμα (soma, body) due to their property of being very strongly stained by particular dyes. Chromosomes vary widely between different organisms. The DNA molecule may be circular or linear, and can be composed of 10,000 to 1,000,000,000 nucleotides in a long chain. Typically eukaryotic cells (cells with nuclei) have large linear chromosomes and prokaryotic cells (cells without defined nuclei) have smaller circular chromosomes, although there are many exceptions to this rule. Furthermore, cells may contain more than one type of chromosome; for example, mitochondria in most eukaryotes and chloroplasts in plants have their own small chromosomes.
In eukaryotes, nuclear chromosomes are packaged by proteins into a condensed structure called chromatin. This allows the very long DNA molecules to fit into the cell nucleus. The structure of chromosomes and chromatin varies through the cell cycle. Chromosomes are the essential unit for cellular division and must be replicated, divided, and passed successfully to their daughter cells so as to ensure the genetic diversity and survival of their progeny. Chromosomes may exist as either duplicated or unduplicated—unduplicated chromosomes are single linear strands, whereas duplicated chromosomes (copied during synthesis phase) contain two copies joined by a centromere. Compaction of the duplicated chromosomes during mitosis and meiosis results in the classic four-arm structure (pictured to the right). Chromosomal recombination plays a vital role in genetic diversity. If these structures are manipulated incorrectly, through processes known as chromosomal instability and translocation, the cell may undergo mitotic catastrophe and die, or it may aberrantly evade apoptosis leading to the progression of cancer.
However, in practice "chromosome" is a rather loosely defined term. In prokaryotes, a small circular DNA molecule may be called either a plasmid or a small chromosome. These small circular genomes are also found in mitochondria and chloroplasts, reflecting their bacterial origins. The simplest chromosomes are found in viruses: these DNA or RNA molecules are short linear or circular chromosomes that often lack any structural proteins.
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