Definition of chromatid in US English:



  • Each of the two threadlike strands into which a chromosome divides longitudinally during cell division. Each contains a double helix of DNA.

    • ‘There a somatic genetic principle was established whereby mitotic chromosome replication produces sister chromatids that are different from one another.’
    • ‘A double crossover involving one linear chromatid and both chromatids of the circular chromosome generates a linear trimer.’
    • ‘The rate at which heterozygosity is lost depends on the extent to which chromosomes and chromatids segregate randomly during anaphase.’
    • ‘One is the nonreciprocal transfer of information of both DNA strands of a donor chromatid to a chromatid of the homologous chromosome.’
    • ‘Any bias in the segregation of one or the other of a pair of homologous chromosomes or chromatids between the oocyte and the polar body can have a dramatic effect on the genetic makeup of a population.’


Early 20th century: from Greek khrōma, khrōmat- ‘color’ + -id.