Relevance of chromosome mosaicism in preimplantation human embryos

Chromosome errors are a major cause of unsuccessful pregnancies and it is estimated that approximately 50% of spontaneous abortions carry chromosomal abnormalities. Compared to what has been observed among established pregnancies, the rates of chromosome abnormality in preimplantation embryos appear much higher and also the types of abnormalities that are observed are much more diverse. Most interestingly, a large proportion of human preimplantation embryos are mosaic, consisting of both chromosomally normal and abnormal cells. The fate and significance of these abnormal cells in the mosaic preimplantation embryo is still unknown.


The overall objective of this study is to investigate the significance of mosaicism in the human preimplantation embryo. More specifically the aims are to determine:

  1. the incidence of chromosomal mosaicism and the distribution pattern of normal and abnormal cells throughout the stages of early cleavage divisions, and
  2. the effect of mosaicism on embryonic development. 


Fluorescence in situ hybridization (FISH) with chromosome specific DNA probes and microarray technology, such as array CGH, will be used to investigate the chromosome status of human preimplantation embryos.

Principal Investigator:  Asangla Ao, PhD  profile
Other researchers:  Xiao yun Zhang, MSc; Ahmet Yilmaz, PhD