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Decrypting cell division: How to separate sister chromosomes in parallel?
In the field of cytology, the term "full-center chromosome" may not be well known, but its importance in biological evolution cannot be ignored.These chromosomes do not have a distinct centrosome like typical single-center chromosomes, but are scattered with multiple kinetochores along the length of the chromosome.Such a structure allows sister chromatids to separate in parallel during cell division, showing significant biological adaptability.
First, the whole-center chromosome lacks the traditional central contraction, but instead has a dynamic center throughout the chromosome axis.This feature allows microtubulees to effectively bind to chromosomes during cell division.
Evolution and adaptation of whole-center chromosomes
Since 1935, since Austrian biologist Franz Schrader first described the entire center chromosome, researchers have discovered that about eight hundred species possess such chromosomes.These species include plants, insects, arachnids and nematodes.They usually run in cell division in a "parallel movement" manner, rather than a classic "V-shaped" arrangement, showing their evolutionary adaptability.
Study points out that the entire center chromosome can stabilize chromosome fragments caused by accidental double-strand breaks, which means they can effectively prevent the loss of genetic information.
In-depth analysis of the structure of the whole center chromosome
In detailed molecular analysis of the nematode Caenorhabditis elegans, the structure of these chromosomes is clearly depicted.Studies have shown that in these organisms, the dynamic center is formed symmetrically on both faces of the condensed mitotic chromosome, each line representing the diffusion dynamic center of a sister chromosome.Such tissue structure allows broken chromosomal fragments to retain the activity of the dynamic center and perform correct separation.
Full-center chromosomes in different organisms
It is reported that the entire center chromosome exists in different invertebrates, including various insects, scorpions, spiders and polypods.Especially in species such as aphids and phoenix butterflies, the stability of the entire center chromosome is known as a defense mechanism that can resist compounds released by plants that can cause DNA damage.Therefore, such chromosomal structures play an important role in plant-insect interactions.
In some plants, chemicals that cause DNA damage, such as nicotine and caffeine, are present.The structure of the entire center chromosome allows these insects to better withstand these environmental stresses.
Central chromosomes and meiosis
Many species with full-center chromosomes exhibit different behaviors in meiosis than in general patterns.In some species, sister chromosomes are separated in the first half of meiosis, while homologous chromosomes are separated in the second half, forming the so-called "reverse meiosis".The emergence of this phenomenon suggests that we must rethink the interaction between chromosomal dynamics and cell division.
In reverse meiosis, separation of homologous chromosomes is delayed to the second meiosis, which is exactly the opposite of the arrangement of first homologous and later sisters in typical meiosis.
Future research direction
In-depth understanding of the entire center chromosome not only enhances our understanding of the process of cell division, but also provides a new perspective for genomic research.Future research is necessary to focus on comparisons between different species, further revealing the evolutionary process of the entire center chromosome and its environmental adaptability.However, we should probably reflect on whether different biological processes will affect the adaptation of the entire center chromosome?
