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A sister chromatid refers to the identical copies formed by the DNA replication of a chromosome, with both copies joined together by a common centromere. In other words, a sister chromatid may also be said to be 'one-half' of the duplicated chromosome. A pair of sister chromatids is called a dyad.
In the diagram, (1) refers to a chromatid: 1-half of two identical threadlike strands of a replicated chromosome.During cell division, the identical copies (called a "sister chromatid pair") are joined at the region called the centromere (2).
Sister chromatid crossover events are known to occur at a rate of several crossover events per cell per division in eukaryotes. [29] Most of these events involve an exchange of equal amounts of genetic information, but unequal exchanges may occur due to sequence mismatch.
In this diagram of a duplicated chromosome, (2) identifies the centromere—the region that joins the two sister chromatids, or each half of the chromosome. In prophase of mitosis, specialized regions on centromeres called kinetochores attach chromosomes to spindle fibers. The centromere links a pair of sister chromatids together during cell ...
Chromosome segregation is the process in eukaryotes by which two sister chromatids formed as a consequence of DNA replication, or paired homologous chromosomes, separate from each other and migrate to opposite poles of the nucleus. This segregation process occurs during both mitosis and meiosis. Chromosome segregation also occurs in prokaryotes ...
Sister chromatid exchange (SCE) is the exchange of genetic material between two identical sister chromatids. It was first discovered by using the Giemsa staining method on one chromatid belonging to the sister chromatid complex before anaphase in mitosis. The staining revealed that few segments were passed to the sister chromatid which were not ...
The synaptonemal complex (SC) is a protein structure that forms between homologous chromosomes (two pairs of sister chromatids) during meiosis and is thought to mediate synapsis and recombination during prophase I during meiosis in eukaryotes.
During mitosis, each sister chromatid forming the complete chromosome has its own kinetochore. Distinct sister kinetochores can be observed at first at the end of G2 phase in cultured mammalian cells. [17] These early kinetochores show a mature laminar structure before the nuclear envelope breaks down. [18]