epigenetics mechanism.
These are apparenty an important part of transcriptional regulation given the number of modifications they can undergo! Quite exciting.
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A chromosome carries genes and other genetic material. A haplotype records the alleles carried on one chromosome at specified genetic loci.
In a typical eukaryotic cell nucleus, an unreplicated chromosome comprises one long double-stranded DNA molecule with associated proteins; a replicated chromosome comprises two associated sister chromatids. It need not be X-shaped: that familiar outline depicts a condensed, replicated state.[ref]
Cell Division. Biology 2e by Mary Ann Clark and others; §10.1, Genomic DNA; Eukaryotic Chromosomal Structure and Compaction, especially Figure 10.4 and final paragraph
For these ordinary centromere-bearing chromosomes, count by centromere units before separation: the paired sister centromere regions count together as one replicated chromosome. Once sister chromatids separate in anaphase of mitosis or meiosis II, each becomes a daughter chromosome. Thus the undivided anaphase biological cell in the mitotic example transiently contains twelve daughter chromosomes, but each pole receives six and each completed daughter cell nucleus remains diploid. State the counting compartment and stage; summing both poles is not the ploidy of one daughter.