The monocentric chromosome is a chromosome that has only one

centromere The centromere links a pair of sister chromatids together during cell division. This constricted region of chromosome connects the sister chromatids, creating a short arm (p) and a long arm (q) on the chromatids. During mitosis, spindle fiber ...

in a

chromosome A chromosome is a package of DNA containing part or all of the genetic material of an organism. In most chromosomes, the very long thin DNA fibers are coated with nucleosome-forming packaging proteins; in eukaryotic cells, the most import ...

and forms a narrow constriction. Monocentric centromeres are the most common structure on highly repetitive DNA in plants and animals.

Structure

Monocentric chromosomes as compared to holocentric chromosomes where the entire length of the chromosome acts as the centromere. In monocentric chromosomes there is one primary constriction and the centromere its CenH3 loci at this location. Holocentric chromosomes are found throughout the plant and animal kingdoms such as the nematode ''

Caenorhabditis elegans ''Caenorhabditis elegans'' () is a free-living transparent nematode about 1 mm in length that lives in temperate soil environments. It is the type species of its genus. The name is a Hybrid word, blend of the Greek ''caeno-'' (recent), ''r ...

''. Holocentric chromosomes do have an evolutionary advantage by preventing the loss of chromosome after a DNA double-strand break. The centromere is the point of attachment for the mitotic apparatus

Chromosomal aberrations

Deletions, duplications and translocations can produce a polycentric chromosome. This is troublesome for cells that divide often since at the time of

anaphase Anaphase () is the stage of mitosis after the process of metaphase, when replicated chromosomes are split and the newly-copied chromosomes (daughter chromatids) are moved to opposite poles of the cell. Chromosomes also reach their overall maxim ...

the polycentric chromosome does not move to opposite poles of spindle fiber and the cell dies.

References

{{Chromo Chromosomes Classical genetics DNA replication

Structure

Chromosomal aberrations

See also

References