Experimental Factor Ontology entry EFO_0009077 (premature chromatid separation trait) is premature chromatid separation consists of separate and splayed chromatids with discernible centromeres and involves all or most chromosomes of a metaphase. It is found in up to 2% of metaphases in cultured lymphocytes from approximately 40% of normal individuals. When PCS is present in 5% or more of cells, it is known as the 'heterozygous PCS trait' and has no obvious phenotypic effect, although some have reported decreased fertility (Gabarron et al., 1986). Inheritance is autosomal codominant (Kajii and Ikeuchi, 2004).