Homologous centromeres compete for segregation to the secondary oocyte nucleus at female meiosis I. Centromeric repeats also compete with each other to populate centromeres in mitotic cells of the germline and have become adapted to use the recombinational machinery present at centromeres to promote their own propagation. Repeats are not needed at centromeres, rather centromeres appear to be hospitable habitats for the colonization and proliferation of repeats. This is probably an indirect consequence of two distinctive features of centromeric DNA. Centromeres (...) are subject to breakage by the mechanical forces exerted by microtubules and meiotic crossing‐over is suppressed. Centromeric proteins acting in trans are under selection to mitigate the costs of centromeric repeats acting in cis. Collateral costs of mitotic competition at centromeres may help to explain the high rates of aneuploidy observed in early human embryos. (shrink)

Modern science developed in the interflow of culture between west and east. Combing of pratice technology with philosophic thoughts formed experimental method. Holistic views contacting atomism produced system theory. System thoughts are applicated in the science and engineering of biosystems, and the cencepts of system biomedicine (Kamada T.1992), systems biology (Zieglgansberger W, Tolle TR.1993), system bioengineering and system genetics (Zeng BJ. 1994) were established. From positive to synthetic thoughts, philosophy have been developed ontology, cosmology, organism theories. Structurity is structure logic (...) system founded on entity, develop, exist axioms, tolerance, adaptation, fluctuate, interweave, transform theorems and integrate, adaptation, construct laws. Structurity be discussed on the cosmos, life, culture system, creation, hologram theories of structure ontology, construct mutation, simi-structure organism and entity emergence, symbol implication. From the relation of structure, function and development, the structurity put forward the cycle, spiral, triangle structure stability patterns of self-organization in structure complement each other and stratification, functional couple and interflow bounds growth, coordinativetransformation and holographic symmetry. (shrink)