Cytogenetic analysis of human embryos and embryonic stem cells derived from monopronuclear zygotes.
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.
Liao
Hongqing
H
Institute of Reproductive and Stem Cell Engineering, Central South University, Changsha, Hunan, China.
Zhang
Shuoping
S
Cheng
Dehua
D
Ouyang
Qi
Q
Lin
Ge
G
Gu
Yifan
Y
Lu
Changfu
C
Gong
Fei
F
Lu
Guangxiu
G
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