Recently, several authors have proposed strategies for correction of triploidy based on the removal of the extra pronucleus at the zygote stage. In the present bioassay, the following were analysed: (1) the different factors that can induce the formation of multipronuclear zygotes in mammals; (2) the different morphological patterns established according to the number of pronuclei and polar bodies that can be observed at the zygote stage and used to distinguish the origin of multipronuclear zygotes; and (3) the pattern of chromosomal segregation during the first mitotic division and ploidy status of the resulting preimplantation embryos. Such an analysis shows that the morphological criterion of counting the number of pronuclei and polar bodies can be misleading and should not be used for ascertaining the origin of tripronuclear zygotes. In addition, although monospermic digynic zygotes have a single sperm centromere, which likely organizes a single bipolar spindle during the first mitotic division, more data on chromosomal distribution and segregation of digynic tripronuclear zygotes should be collected before strategies for correction of triploidy are implemented in humans.
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http://dx.doi.org/10.1071/rd99057 | DOI Listing |
J Assist Reprod Genet
January 2023
State Key Laboratory of Reproductive Medicine, The Center for Clinical Reproductive Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, People's Republic of China.
Purpose: To investigate the genetic causes of polyspermy and total fertilization failure (TFF) in two independent male patients suffering from male infertility.
Methods: Immunofluorescence (IF) staining was used to detect the localization of the PLCζ protein in sperm and the maternal pronucleus in the zygote. Genomic DNA samples were extracted from the peripheral blood of patients and their families.
J Assist Reprod Genet
September 2017
Reproductive and Genetic Hospital of CITIC-XIANGYA, Changsha, China.
Purpose: The purpose of this study was to investigate the cause of repeated multipronucleus (MPN) formation in zygotes in a patient after both in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI).
Method: This is a case study. A patient had unexplained primary infertility with recurring total MPN zygotes after IVF and ICSI cycles.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi
August 2010
Department of Reproductive Medicine, the Third Affiliated Hospital of Guangzhou Medical College, Guangzhou, Guangdong, 510150 PR China.
Objective: To compare the development of abnormal pronuclear zygotes after intracytoplasmic sperm injection (ICSI) and analyze their genetic polymorphism.
Methods: Four hundred and ninety three abnormal pronuclear zygotes after ICSI were divided into three groups based on the number of pronuclei: 347 nonpronuclear oocytes, 71 monopronuclear zygotes and 75 multipronuclear zygotes. All of them were cultured in the medium of Vitrolife G5 series(TM).
BMC Dev Biol
March 2008
Department of Obstetrics and Gynaecology, Radboud University Nijmegen Medical Centre, P,O, Box 9101, 6500 HB Nijmegen, The Netherlands.
Background: about 15% to 30% of the DNA in human sperm is packed in nucleosomes and transmission of this fraction to the embryo potentially serves as a mechanism to facilitate paternal epigenetic programs during embryonic development. However, hitherto it has not been established whether these nucleosomes are removed like the protamines or indeed contribute to paternal zygotic chromatin, thereby potentially contributing to the epigenome of the embryo.
Results: to clarify the fate of sperm-derived nucleosomes we have used the deposition characteristics of histone H3 variants from which follows that H3 replication variants present in zygotic paternal chromatin prior to S-phase originate from sperm.
Reprod Biomed Online
December 2002
Shady Grove Fertility Reproductive Science Centre, Rockville, MD, USA.
The purpose of this study was to demonstrate the safety and efficacy of vitrification of human pronuclear stage (PN) embryos in the human assisted reproduction laboratory. Using single pronucleate (1PN) and three pronucleate (3PN) zygotes, the impact of vitrification in the Flexipet denuding pipette (FDP) as a carrier was assessed in terms of survival, embryonic development and blastocyst formation when compared according to the PN number, and unvitrified controls. A total of 65 1PN and 152 3PN zygotes were vitrified; after warming 82% (53/65) of 1PN and 90% (137/152) of 3PN survived.
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