The position of interphase chromosomes and late replicating DNA in centromere and telomere regions of Allium cepa L.

Chromosomes in G₁, S, G₂ and early prophase of Allium cepa root tip nuclei are oriented in the same position as telophase chromosomes. The centromeric heteroehromatin is aggregated in a chromocenter at one side of the nucleus, the telomeres scattered at the opposite side. Telomeres appear to associate with other telomeres in interphase in a roughly two by two fashion. Telomere-centromere DNA is late replicating. These results support the conclusion that chromosomes in higher organisms frequently maintain their telophase orientation from the end of telophase, during interphase and well into the next prophase.