John E. Rice

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Mitochondrial DNA control region sequences were analyzed from 162 wolves at 27 localities worldwide and from 140 domestic dogs representing 67 breeds. Sequences from both dogs and wolves showed considerable diversity and supported the hypothesis that wolves were the ancestors of dogs. Most dog sequences belonged to a divergent monophyletic clade sharing no(More)
We describe a highly accurate method for determining the sex of human embryos via real-time polymerase chain reaction (PCR) amplification of highly-conserved, moderately-repeated sequences within the TSPY genes on the Y chromosome and the U2 genes on chromosome 17. Individual male lymphocytes, female lymphocytes, and blastomeres from donated cleavage-stage(More)
Life abounds with genetic variations writ in sequences that are often only a few hundred nucleotides long. Rapid detection of these variations for identification of genetic diseases, pathogens and organisms has become the mainstay of molecular science and medicine. This report describes a new, highly informative closed-tube polymerase chain reaction (PCR)(More)
Conventional asymmetric PCR is inefficient and difficult to optimize because limiting the concentration of one primer lowers its melting temperature below the reaction annealing temperature. Linear-After-The-Exponential (LATE)-PCR describes a new paradigm for primer design that renders assays as efficient as symmetric PCR assays, regardless of primer ratio.(More)
Xist RNA localizes to the inactive X chromosome in cells of late cleavage stage female mouse embryos (Sheardown et al., 1997: Cell 91:99-107). Fluorescence in situ hybridization (FISH), however, does not quantify the number of Xist transcripts per nucleus. We have used real-time reverse transcription-polymerase chain reaction (RT-PCR) to measure Xist RNA(More)
The results presented here provide the first single-cell genetic assay for Tay-Sachs disease based on real-time PCR. Individual lymphoblasts were lysed with an optimized lysis buffer and assayed using one pair of primers that amplifies both the wild type and 1278 + TATC Tay-Sachs alleles. The resulting amplicons were detected in real time with two molecular(More)
Xist gene expression begins at the late 2-cell stage in female mouse embryos and by the third division results in the accumulation of an average 100 copies of Xist RNA per cell, as measured by real-time reverse transcription-polymerase chain reaction (RT-PCR). In the blastocyst, the trophectoderm maintains the paternally imprinted pattern of Xist expression(More)
Traditional asymmetric PCR uses conventional PCR primers at unequal concentrations to generate single-stranded DNA. This method, however, is difficult to optimize, often inefficient, and tends to promote nonspecific amplification. An alternative approach, Linear-After-The-Exponential (LATE)-PCR, solves these problems by using primer pairs deliberately(More)
Amplification of DNA sequencesfrom single cells via PCR is increasingly used in basic research and clinical diagnostics but remains technically difficult. We have developed a cell lysis protocol that uses an optimized proteinase K solution, named QuantiLyse and permits reliable amplification from individual cells. This protocol was compared to other(More)
This protocol describes the design and execution of monoplex and multiplex linear-after-the-exponential (LATE)-PCR assays using a novel reagent, PrimeSafe, that suppresses all forms of mispriming. LATE-PCR is an advanced form of asymmetric amplification that uses a limiting primer and an excess primer for efficient exponential amplification of(More)