Number of cell divisions before the mid-blastula transition

Value 12 cell divisions
Organism African clawed frog Xenopus laevis
Reference Newport J, Kirschner M. A major developmental transition in early Xenopus embryos: I. characterization and timing of cellular changes at the midblastula stage. Cell. 1982 Oct30(3):675-86 abstractPubMed ID6183003
Method Abstract: "The Xenopus embryo undergoes 12 rapid synchronous cleavages followed by a period of slower asynchronous divisions more typical of somatic cells."
Comments Abstract: "[Researchers] have investigated the timing of the MBT [midblastula transition] and found that it does not depend on cell division, on time since fertilization or on a counting mechanism involving the sequential modification of DNA."
Entered by Paul Jorgensen
ID 101950