Maize centromeres expand and adopt a uniform size in the genetic background of oat

A diagrammatic illustration of reposition and expansion of maize Cen3 in the genetic background of oat. (A) Cen3 repositioned to a short-arm domain that is ∼16 Mb away from its original location, resulting in a neocentromere nCen3. nCen3 has also significantly expanded compared to Cen3. (B) A misdivision occurred in nCen3. The red arrow points to the approximate position of the misdivision. The red bar represents the centromeric DNA (Cent C and CRM repeats) associated with the original Cen3. (C) The short arm derived from the misdivision formed an isochromosome. (D) The centromere of the original isochromosome expanded, resulting in the current version of nCenM3.