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Abstract Background Meiotic recombination is one of the important phenomena contributing to gamete genome diversity. However, except for human and a few model organisms, it is not well studied in livestock, including cattle. Results To investigate their distributions in the cattle sperm genome, we sequenced 143 single sperms from two Holstein bulls. We mapped meiotic recombination events at high resolution based on phased heterozygous single nucleotide polymorphism (SNP). In the absence of evolutionary selection pressure in fertilization and survival, recombination events in sperm are enriched near distal chromosomal ends, revealing that such a pattern is intrinsic to the molecular mechanism of meiosis. Furthermore, we further validated these findings in single sperms with results derived from sequencing its family trio of diploid genomes and our previous studies of recombination in cattle. Conclusions To our knowledge, this is the first large-scale single sperm whole-genome sequencing effort in livestock, which provided useful information for future studies of recombination, genome instability, and male infertility.

Background: Meiotic recombination is one of the important phenomena contributing to gamete genome diversity. However, except for human and a few model organisms, it is not well studied in livestock, including cattle. Results: To investigate their distributions in the cattle sperm genome, we sequenced 143 single sperms from two Holstein bulls. We mapped meiotic recombination events at high resolution based on phased heterozygous single nucleotide polymorphism (SNP). In the absence of evolutionary selection pressure in fertilization and survival, recombination events in sperm are enriched near distal chromosomal ends, revealing that such a pattern is intrinsic to the molecular mechanism of meiosis. Furthermore, we further validated these findings in single sperms with results derived from sequencing its family trio of diploid genomes and our previous studies of recombination in cattle. Conclusions: To our knowledge, this is the first large-scale single sperm whole-genome sequencing effort in livestock, which provided useful information for future studies of recombination, genome instability, and male infertility. [ABSTRACT FROM AUTHOR]

Abstract Background Patients with severe oligospermia and nonobstructive azoospermia have very limited numbers of viable sperm in their epididymal and testicular samples. Thus, cryopreservation of their sperm is performed to avoid repeated sperm retrievals and to preserve their sperm from any side effects of any treatment regimens. Main body The development of intracytoplasmic sperm injection technology has extended the therapeutic capacity of assisted reproductive technology for men with azoospermia via the surgical or percutaneous isolation of sperm from the testis/epididymis. The conventional cryopreservation techniques are inadequate for preserving individually selected sperm. The technique for freezing single sperm was first developed in 1997 and has been explored from the perspective of frozen carriers, freezing programs, and cryoprotectant formulations. Among these methods, advances in frozen carriers have directly improved single-sperm freezing technology. In this review, we evaluate the different technologies for the cryopreservation of single sperm by discussing the advantages and disadvantages of different freezing methods, their clinical applications, and the outcomes for a range of frozen carriers. Conclusion Our review article describes the latest and current technologies implemented for the cryopreservation of single sperm that could potentially benefit patients with severe oligospermia and who rarely have any sperm in their ejaculate. This review provides a platform to understand the process and pitfalls of single-sperm cryopreservation to ensure further improvements in the cryopreservation technology in future studies.

Autosomal dominant hereditary polycystic kidney disease (ADPKD) is the most common inherited kidney disease that causes end‐stage renal disease and kidney failure. Preimplantation genetic testing for monogenic (PGT‐M) can effectively prevent the transmission of genetic diseases from parents to the offspring before pregnancy. However, PGT‐M currently adopts the single nucleotide polymorphism (SNP) linkage analysis for embryo's pathogenic gene carrying status and linkage analysis requires proband of the family. Here we report a new PGT‐M strategy using single sperm SNP linkage analysis for male patient with sporadic ADPKD caused by de novo PKD1 mutation. We recruited five couples with male patient with ADPKD caused by de novo PKD1 mutation, and 39 embryos from six PGT‐M cycles were detected. The five couples had at least one embryo that does not carry the PKD1 mutation. Within these five couples, the accuracy of carrier status of embryos was confirmed by amniotic fluid gene detection of two couples and two couples successfully delivered healthy fetuses. Therefore, the new PGT‐M strategy of using single sperm SNP linkage analysis was proved to be feasible and effective for male patient with ADPKD caused by de novo PKD1 mutation. [ABSTRACT FROM AUTHOR]

Background: Patients with severe oligospermia and nonobstructive azoospermia have very limited numbers of viable sperm in their epididymal and testicular samples. Thus, cryopreservation of their sperm is performed to avoid repeated sperm retrievals and to preserve their sperm from any side effects of any treatment regimens. Main body: The development of intracytoplasmic sperm injection technology has extended the therapeutic capacity of assisted reproductive technology for men with azoospermia via the surgical or percutaneous isolation of sperm from the testis/epididymis. The conventional cryopreservation techniques are inadequate for preserving individually selected sperm. The technique for freezing single sperm was first developed in 1997 and has been explored from the perspective of frozen carriers, freezing programs, and cryoprotectant formulations. Among these methods, advances in frozen carriers have directly improved single-sperm freezing technology. In this review, we evaluate the different technologies for the cryopreservation of single sperm by discussing the advantages and disadvantages of different freezing methods, their clinical applications, and the outcomes for a range of frozen carriers. Conclusion: Our review article describes the latest and current technologies implemented for the cryopreservation of single sperm that could potentially benefit patients with severe oligospermia and who rarely have any sperm in their ejaculate. This review provides a platform to understand the process and pitfalls of single-sperm cryopreservation to ensure further improvements in the cryopreservation technology in future studies. [ABSTRACT FROM AUTHOR]

Abstract: Sex-sorted bovine semen has become a valuable tool in animal production for sex preselection. Development of novel sperm sexing technologies, or evaluation of the quality of existing methods, often requires a single-sperm, sex-typing method that is reliable and easy to perform. In the present study, we report the development, validation, and application of a simple, reliable, and cost-effective method for single-sperm sex typing using nested polymerase chain reaction (PCR), based on the amelogenin gene. Several hundred single sperm were isolated using a simple manual technique, or a high-speed flow-sorter, and were successfully sex-typed using the amelogenin nested PCR. Based on the pooled results of individual sperm, there was no significant difference in the semen sex ratio of unsorted (44.6% X-sperm and 55.4% Y-sperm) or X/Y-sorted semen (91.4% X-sperm and 94.0% Y-sperm), as compared to the expected ratio in unsorted semen or the post-sorting reanalysis data, respectively. The amelogenin single-sperm sexing method was an adaptable, accurate, and reliable tool for single-sperm sex typing. [Copyright &y& Elsevier]

Organization of the IGHV genes (n=108) on single human chromosomes has been determined by detecting these sequences in single sperm using multiplex PCR amplification followed by microarray detection. A total of 374 single sperm samples from five Caucasian males were studied. Three deletion/insertion polymorphisms (Del I-Del III) with deletion allele frequencies ranging from 0.1 to 0.3 were identified. Del I is a previously reported polymorphism affecting three IGHV genes (IGHV1-8, IGHV3-9, and IGHV2-10). Del II affects a region 2-18?kb containing two pseudogenes IGHV(II)-28.1 and IGHV3-29, and Del III spans~21-53?kb involving genes IGHV4-39, IGHV7-40, IGHV(II)-40-1, and IGHV3-41. Deletion alleles of both Dels II and III were found in a heterozygous state, and therefore, could not be easily detected if haploid samples were not used in the study. Results of the present study indicate that deletions/insertions together with other possible chromosomal rearrangements may play an important role in forming the genetic structure of the IGHV region, and may significantly contribute to antibody diversity. Since these three polymorphisms are located within or next to the 3'half of the IGHV region, they may have an important role in the expressed IGHV gene repertoire during immune response.Genes and Immunity (2005) 6, 186-193. doi:10.1038/sj.gene.6364176 Published online 3 March 2005 [ABSTRACT FROM AUTHOR]

Abstract: The identification of individuals using short tandem repeat (STR) analysis is important in forensic investigation. STR analysis is especially difficult using DNA from a single nucleus. In this study, DNA from a single sperm from a semen smear stained with hematoxylin and eosin (H&E) was captured using a laser microdissection method and amplified using the improved primer extension preamplification (I-PEP) polymerase chain reaction (PCR) method. Amplified DNA was used for STR analysis with the original and 3% primer methods. DNA from 15 STR loci and the amelogenin locus was amplified using an AmpFlSTR® PCR Amplification kit (Applied Biosystems). Using the original primer method, it was impossible to genotype the 15 STR loci (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818, and FGA). While using less primer (3% dilution), the 15 STR loci and amelogenin locus were determined perfectly in all of the preserved single sperms. Therefore, the reduced primer method is more efficient for analyzing STR loci from a single sperm captured by laser microdissection. [Copyright &y& Elsevier]

Sequencing the entire genome of single sperm cells can provide valuable information of the distribution of meiotic recombination events in eukaryotic genomes. Here, we provide a description of the experimental work flow for isolating single sperm cells from the microcrustacean Daphnia pulex using fluorescence-activated cell sorting. Moreover, we describe the application of a whole-genome amplification technique (i.e., Multiple Annealing and Looping Based Amplification Cycles method) to single sperm of Daphnia to generate enough DNA for library preparation of next-generation sequencing.