Polycentric chromosome
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In
genetics Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinians, Augustinian ...
, a polycentric chromosome is any
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 ...
featuring multiple
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 ...
s. Polycentric chromosomes are produced by chromosomal aberrations such as deletion, duplication, or translocation. Polycentric chromosomes usually result in the death of the cell because polycentric chromosomes may fail to move to opposite poles of
spindle fiber In cell biology, the spindle apparatus is the cytoskeletal structure of eukaryotic cells that forms during cell division to separate sister chromatids between daughter cells. It is referred to as the mitotic spindle during mitosis, a process t ...
during
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 ...
. As a result, the chromosome is fragmented, which causes the death of the cell. In some
algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...
, such as ''
Spirogyra ''Spirogyra'' (common names include water silk, mermaid's tresses, and blanket weed) is a genus of filamentous charophyte green algae of the order Zygnematales, named for the helical or spiral arrangement of the chloroplasts that is charact ...
'', polycentric chromosomes appear normally. They also occur in the sedge, ''
Luzula ''Luzula'' is a genus of flowering plants in the rush family Juncaceae. The genus has a cosmopolitan distribution, with species occurring throughout the world, especially in temperate regions, the Arctic, and higher elevation areas in the tropic ...
''.


References

Chromosomes {{genetics-stub