The central localization of the small and early replicating chromosomes in human diploid metaphase figures

Centromere-center distances are analyzed in 700 metaphase plates, which belong to four different samples. The descriptive analysis of the chromosome distribution shows that smaller, earlier replicating, gene-dense chromosomes are preferentially found near the metaphase plate center, surrounded by longer chromosomes which finish their replication rather late during S phase. This general pattern is highly constant in diploid metaphase samples and independent of sex, culture time, and number of individuals used in the sample. There is accumulating evidence that this overall distribution is not the result of technical artifacts.