ISSN:
1573-7330
Keywords:
polymerase chain reaction
;
single cell
;
DNA amplification
;
human preimplantation embryo
;
preimplantation diagnosis
;
sexing
;
alphoid repeat
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Introduction: Preimplantation diagnosis involves detecting genetic defects in one or two blastomeres biopsied from cleavage stage embryos followingin vitro fertilization (IVF). For X-linked recessive disease, identification of the sex of embryos allows transfer of only unaffected females. To examine how critical the preparation of the single blastomere is for amplification of a Y chromosome specific repeat sequence using the polymerase chain reaction (PCR), the incidence of amplification failure has been examined following two lysis protocols. Materials and Methods: Amplification of a Y alphoid repeat sequence from single blastomeres disaggregated from cleavage stage embryos was examined after either (1) lysis in distilled water and freeze-thawing twice or (2) a two-step lysis protocol involving an initial treatment in potassium hydroxide and dithiothreitol. Some of the embryos had been previously sexed by cleavage-stage biopsy and fluorescent in situ hybridization with X- and Y-specific probes. Results: Amplification failure occurred in 6 of 50 (12%) and 4 of 60 (7%) single blastomeres from male embryos following lysis in distilled water or using the two-step protocol, respectively. Conversely, amplification from contaminating DNA occurred in 5 of 63 (8%) single blastomeres from female embryos and 6 of 94 (6%) of control medium blanks. Conclusions: The incidence of amplification failure was improved but not eliminated using the two-step lysis protocol. At least two cells, therefore, would be necessary for accurate identification of males by amplification of Y-specific repeat sequences alone. Nevertheless, this protocol for preparing cleavage-stage blastomeres is likely to give more consistent amplification of any unique or repeat sequences.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02072533
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