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Latest Meiosis Stories

2011-08-29 12:07:09

Most cells rely on structural tethers to position chromosomes in preparation for cell division. Not so oocytes. Instead, a powerful intracellular stream pushes chromosomes far-off the center in preparation for the highly asymmetric cell division that completes oocyte maturation upon fertilization of the egg, report researchers at the Stowers Institute for Medical Research. Their findings illustrate how oocytes repurposed a dynamic cellular mechanism capable of generating considerable...

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2011-08-18 13:48:11

When an egg cell is being formed, the cellular machinery which separates chromosomes is extremely imprecise at fishing them out of the cell's interior, scientists at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany, have discovered. The unexpected degree of trial-and-error involved in this process could explain why errors in the number of chromosomes in the egg cell are the leading cause of miscarriages and severe congenital diseases such as trisomies like Down's...

2011-08-08 06:43:56

The human genome is peppered with repeated DNA elements that can vary from a few to thousands of consecutive copies of the same sequence. During meiosis"”the cell division that produces sperm and eggs"”repetitive elements place the genome at risk for dangerous rearrangements from genome reshuffling. This recombination typically does not occur in repetitive DNA, in part because much of it is assembled into specialized heterochromatin. Other mechanisms that restrain recombination in...

2011-07-05 12:14:03

Ovarian stimulation undertaken by women of advanced maternal age (over 35 years) receiving fertility treatment may be disrupting the normal pattern of meiosis "“ a critical process of chromosome duplication followed by two specialized cell divisions in the production of oocytes and sperm "“ and leading to abnormalities of chromosome copy numbers (aneuploidy) that result in IVF failure, pregnancy loss or, more rarely, the birth of affected children with conditions such as Down's...

2011-07-04 12:49:36

ESHRE study may answer the question in older women Ovarian stimulation undertaken by women of advanced maternal age (over 35 years) receiving fertility treatment may be disrupting the normal pattern of meiosis "“ a critical process of chromosome duplication followed by two specialised cell divisions in the production of oocytes and sperm "“ and leading to abnormalities of chromosome copy numbers (aneuploidy) that result in IVF failure, pregnancy loss or, more rarely, the birth of...

2011-04-14 21:03:08

Egg cells failing to properly arrange chromosomes Washington State University researchers have confirmed a critical step in cell division that results in age-related miscarriages and birth defects, including Down syndrome. Writing in the upcoming issue of the journal "Current Biology," the researchers say they recreated the conditions in which an egg cell will continue to undergo cell division without properly arranging its chromosomes, creating offspring with aneuploidy, or an abnormal...

2010-09-09 10:51:51

University of Pennsylvania biologists studying human reproduction have identified what is likely the major contributing factor to the maternal age-associated increase in aneuploidy, the term for an abnormal number of chromosomes during reproductive cell division. Using naturally aging mouse models, researchers showed that this basic fact of reproductive life is most likely caused by weakened chromosome cohesion.  Older oocytes, or egg cells, have dramatically reduced amounts of a...

2010-07-29 17:13:22

A genetics research team based at The Children's Hospital of Philadelphia continues to discover recurrent translocations"”places in which two chromosomes exchange pieces of themselves. As many as 1 in 600 persons carry balanced chromosome translocations, which involve no loss or gain of DNA. Most such people appear healthy, but may have a child with abnormal chromosome composition and disabilities resulting from disrupted, extra or missing copies of genes. While rare, such diseases...

2010-06-11 01:11:06

The research demonstrates that p53 is activated to control the creation of ova and spermatozoa Protein p53 is known as the guardian of the genome since it is basic for the genome's integrity by preventing the accumulation of mutations originating either by the cell's own mechanisms or by the action of external agents. The protein becomes activated in response to specific signals such as breaks in DNA. This activation implies a slowing of the cell's cycle which allows it to repair itself from...

2010-06-07 13:46:59

Protein p53 is also activated to control the creation of ova and spermatozoids Protein 53 is very important in protecting against cancer given that it prevents cancer-causing mutations from accumulating and its inactivation is closely linked to the proliferation of tumour cells. UAB lecturer Ignasi Roig participated in the study. Formed by an international research team, the study served to discover that this protein played an unexpected physiological role: it also becomes activated during...


Word of the Day
reremouse
  • A bat.
The word 'reremouse' comes from Middle English reremous, from Old English hrēremūs, hrērmūs ("bat"), equivalent to rear (“to move, shake, stir”) +‎ mouse.
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