title: Cytogenetic analysis of human embryos and embryonic stem cells derived from monopronuclear zygotes.
abstract: OBJECTIVE
  By comparing the chromosomal constitution among the arrested cleavage-stage embryos, blastocysts and human embryonic stem cells (hESCs) which are all derived from monopronuclear (1PN) zygotes, it is aimed to determine whether chromosomally normal embryos can be reliably selected by blastocyst culture.
  
  
  METHODS
  After 1PN zygotes are sequentially cultured for 5 days, the blastocysts and arrested cleavage-stage embryos were analyzed by fluorescence in situ hybridization (FISH) with probes for chromosomes 18, X and Y; G-banding analysis was adopted to analyze the karyotype of 1PN hESCs.
  
  
  RESULTS
  The diploid rate of blastocysts was 74.6%, which was significantly (P < 0.001) higher than that of arrested cleavage-stage embryos (31.6%), and the diploid rate of hESCs was 97.0%, which was significantly (P < 0.01) higher than that of blastocysts; the haploid embryos were excluded by blastocyst culture; nevertheless, there still existed such chromosomal abnormalities as mosaic and monosomic in blastocysts and trisomy in hESCs.
  
  
  CONCLUSIONS
  Blastocyst culture is an effective method to select against chromosomal abnormalities, especially the haploids in 1PN embryos; however, development to the blastocyst stage is not a reliable marker for mosaicism or aneuploidy.
authors.affiliation: Institute of Reproductive and Stem Cell Engineering, Central South University, Changsha, Hunan, China.
authors.forename: Hongqing
authors.initials: H
authors.lastname: Liao
authors.forename: Shuoping
authors.initials: S
authors.lastname: Zhang
authors.forename: Dehua
authors.initials: D
authors.lastname: Cheng
authors.forename: Qi
authors.initials: Q
authors.lastname: Ouyang
authors.forename: Ge
authors.initials: G
authors.lastname: Lin
authors.forename: Yifan
authors.initials: Y
authors.lastname: Gu
authors.forename: Changfu
authors.initials: C
authors.lastname: Lu
authors.forename: Fei
authors.initials: F
authors.lastname: Gong
authors.forename: Guangxiu
authors.initials: G
authors.lastname: Lu
mesh_terms: D001755:Blastocyst / Q000166:cytology / Q000648:ultrastructure*; D016009:Chi-Square Distribution; D002869:Chromosome Aberrations / Q000196:embryology*; D002877:Chromosomes, Human; D020732:Cytogenetic Analysis / Q000379:methods*; D053595:Embryonic Stem Cells / Q000166:cytology / Q000648:ultrastructure*; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods; D008297:Male; D011003:Ploidies; D011247:Pregnancy; D019836:Preimplantation Diagnosis / Q000379:methods