This study presents a method for whole genome amplification from a single cell using primer extension preamplification (PEP). The method involves repeated primer extensions using a mixture of 15-base random oligonucleotides to amplify DNA sequences present in a single haploid cell. The researchers estimated that at least 78% of the genomic sequences in a single human haploid cell can be amplified no less than 30 times. This method has significant implications for genetic analysis, including multipoint mapping by sperm or oocyte typing, genetic disease diagnosis, forensics, and the analysis of ancient DNA samples. The PEP method was tested using single sperm DNA, where multiple rounds of primer extension were performed using a mixture of random primers. The results showed that the method can amplify DNA sequences from a single sperm to a level sufficient for analysis. The researchers also tested the amplification of 12 specific DNA sequences and found that the probability of amplifying any sequence to a minimum of 30 copies is at least 0.78 with 95% confidence. The study also discusses the implications of PEP for single cell analysis, including the ability to analyze multiple genetic loci from a single sperm. The method allows for the analysis of a large number of polymorphisms, which is important for genetic mapping. Additionally, the method has potential applications in preimplantation genetic diagnosis and the analysis of small DNA samples, such as those from forensic or ancient DNA sources. The study concludes that PEP is a promising method for amplifying DNA from a single cell, which can be used for various genetic analyses. The method is efficient and does not require extensive manipulation of the sample, making it suitable for a wide range of applications. The researchers also note that further improvements in the PEP method could lead to even higher copy numbers of DNA sequences.This study presents a method for whole genome amplification from a single cell using primer extension preamplification (PEP). The method involves repeated primer extensions using a mixture of 15-base random oligonucleotides to amplify DNA sequences present in a single haploid cell. The researchers estimated that at least 78% of the genomic sequences in a single human haploid cell can be amplified no less than 30 times. This method has significant implications for genetic analysis, including multipoint mapping by sperm or oocyte typing, genetic disease diagnosis, forensics, and the analysis of ancient DNA samples. The PEP method was tested using single sperm DNA, where multiple rounds of primer extension were performed using a mixture of random primers. The results showed that the method can amplify DNA sequences from a single sperm to a level sufficient for analysis. The researchers also tested the amplification of 12 specific DNA sequences and found that the probability of amplifying any sequence to a minimum of 30 copies is at least 0.78 with 95% confidence. The study also discusses the implications of PEP for single cell analysis, including the ability to analyze multiple genetic loci from a single sperm. The method allows for the analysis of a large number of polymorphisms, which is important for genetic mapping. Additionally, the method has potential applications in preimplantation genetic diagnosis and the analysis of small DNA samples, such as those from forensic or ancient DNA sources. The study concludes that PEP is a promising method for amplifying DNA from a single cell, which can be used for various genetic analyses. The method is efficient and does not require extensive manipulation of the sample, making it suitable for a wide range of applications. The researchers also note that further improvements in the PEP method could lead to even higher copy numbers of DNA sequences.