from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The most condensed and constricted region of a chromosome, to which the spindle fiber is attached during mitosis.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The central region of a eukaryotic chromosome where the kinetochore is assembled.
from the GNU version of the Collaborative International Dictionary of English
- n. a specialized condensed region of a chromosomes that appears during mitosis where the chromatids are held together to form an X shape.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a specialized condensed region of each chromosome that appears during mitosis where the chromatids are held together to form an X shape
Furthermore, it has been possible to throw light on problems of crossing-over, as in the demonstration (Muller, Stone, and Offermann, 1930 et seq.) that to whatever position the centromere is moved, it causes a strong inhibition of crossing-over, the strength of which gradually diminishes with distance.
Each chromosome is identifiable by its relative length, by the location of its centromere, which is readily observed at the pachytene stage, and by the individuality of the chromomeres strung along the length of each chromosome.
Each chromosome has a constriction point called the centromere, which divides the chromosome into two sections, or "arms."
To differentiate this homology-independent centromeric association from the regular pairing between homologous chromosomes this phenomenon has been referred to as centromere coupling
Recently, the homology-independent pairwise association of centromeres, termed centromere coupling, was also reported in budding yeast.
I showed how one extra centromere may not result in inevitable damage to the chromosome during meiosis and mitosis, and demonstrated that the fusion did not necessarily have to result in greatly decreased fertility.
It is the remnants of two telomeric regions fusing and it appears to be old, possibly millions of years old based on the divergence of chimp centromere 2q.
I am a cumulonimbus of doubt that centromere sequence can be obtained from Neanderthal remains.
RF: There is a type of chromosome polymorphism which does not harm fertility of hybrides, so-called Robertson's translocation, when two one-armed chromosomes join in centromere to form one two-arm chromosome.
The cartoon in your first post is wrong as it shows a Robertsonian fusion in which one arm of the centromere is lost.
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