Editing Centromere (section)

== Inheritance ==
Since centromeric DNA sequence is not the key determinant of centromeric identity in [[metazoans]], it is thought that [[epigenetic inheritance]] plays a major role in specifying the centromere.<ref>{{cite journal | vauthors = Dalal Y | title = Epigenetic specification of centromeres | journal = Biochemistry and Cell Biology | volume = 87 | issue = 1 | pages = 273–282 | date = February 2009 | pmid = 19234541 | doi = 10.1139/O08-135 }}</ref> The daughter chromosomes will assemble centromeres in the same place as the parent chromosome, independent of sequence. It has been proposed that histone H3 variant [[CENPA|CENP-A]] (Centromere Protein A) is the epigenetic mark of the centromere.<ref>{{cite journal | vauthors = Bernad R, Sánchez P, Losada A | title = Epigenetic specification of centromeres by CENP-A | journal = Experimental Cell Research | volume = 315 | issue = 19 | pages = 3233–3241 | date = November 2009 | pmid = 19660450 | doi = 10.1016/j.yexcr.2009.07.023 }}</ref> The question arises whether there must be still some original way in which the centromere is specified, even if it is subsequently propagated epigenetically. If the centromere is inherited epigenetically from one generation to the next, the problem is pushed back to the origin of the first metazoans.

On the other hand, thanks to comparisons of the centromeres in the X chromosomes, epigenetic and structural variations have been seen in these regions. In addition, a recent assembly of the human genome has detected a possible mechanism of how pericentromeric and centromeric structures evolve, through a layered expansion model for αSat sequences. This model proposes that different αSat sequence repeats emerge periodically and expand within an active vector, displacing old sequences, and becoming the site of kinetochore assembly. The αSat can originate from the same, or from different vectors. As this process is repeated over time, the layers that flank the active centromere shrink and deteriorate. This process raises questions about the relationship between this dynamic evolutionary process and the position of the centromere.<ref>{{Cite journal |last1=Altemose |first1=Nicolas |last2=Logsdon |first2=Glennis A. |last3=Bzikadze |first3=Andrey V. |last4=Sidhwani |first4=Pragya |last5=Langley |first5=Sasha A. |last6=Caldas |first6=Gina V. |last7=Hoyt |first7=Savannah J. |last8=Uralsky |first8=Lev |last9=Ryabov |first9=Fedor D. |last10=Shew |first10=Colin J. |last11=Sauria |first11=Michael E. G. |last12=Borchers |first12=Matthew |last13=Gershman |first13=Ariel |last14=Mikheenko |first14=Alla |last15=Shepelev |first15=Valery A. |date=April 2022 |title=Complete genomic and epigenetic maps of human centromeres |journal=Science |language=en |volume=376 |issue=6588 |pages=eabl4178 |doi=10.1126/science.abl4178 |issn=0036-8075 |pmc=9233505 |pmid=35357911}}</ref>