Patterns of meiotic chromosome segregation were analyzed in cleavage stage and blastocyst stage human embryos from couples with autosomal reciprocal translocations (ART). The influence of quadrivalent asymmetry degree, the presence of terminal breakpoints, and the involvement of acrocentric chromosomes in the rearrangement were analyzed to evaluate their contribution to the formation of non-viable embryos with significant chromosomal imbalance due to pathological segregation patterns and to assess the selection of human embryos by the blastocyst stage. A selection of viable embryos resulting from alternate and adjacent-1 segregation and a significant reduction in the detection frequency of the 3 : 1 segregation pattern were observed in human embryos at the blastocyst stage. The presence of terminal breakpoints increased the frequency of 3 : 1 segregation and was also associated with better survival of human embryos resulting from adjacent-1 mode, reflecting the process of natural selection of viable embryos to the blastocyst stage. The demonstrated patterns of chromosome segregation and inheritance of a balanced karyotype in humans will contribute to optimizing the prediction of the outcomes of in vitro fertilization programs and assessing the risks of the formation of unbalanced embryos for ART carriers.
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http://dx.doi.org/10.3897/compcytogen.18.115070 | DOI Listing |
Front Vet Sci
December 2024
Veterinary Medical Center and College of Veterinary Medicine, Laboratory of Veterinary Embryology and Biotechnology (VETEMBIO), Chungbuk National University, Cheongju, Republic of Korea.
Objective: Myo-inositol (Myo-Ins), the most abundant form of inositol, is an antioxidant and plays a crucial role in the development and reproduction of mammals and humans. However, information elucidating the role of Myo-Ins in porcine embryonic development after parthenogenetic activation (PA) is still lacking. Therefore, we investigated the effect of Myo-Ins on porcine embryos and its underlying mechanisms.
View Article and Find Full Text PDFJ Assist Reprod Genet
December 2024
Department of Obstetrics and Gynecology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
Purpose: Map the nuclear error phenotypes in the two-cell embryo after assisted reproduction using time lapse images and the effect on good quality blastocyst formation.
Methods: Retrospective cohort study using time lapse images, categorizing 2331 two-cell embryos from 392 patient couples and 504 ART cycles categorizing each embryo as mononucleated, multinucleated, micronucleated, binucleated, split nucleation or mixed error. Correlating nuclear error phenotype with good quality blastocyst formation rate (BFR) using contingency tables and unadjusted odds ratio.
J Mol Histol
December 2024
Department of Embryology, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, ACECR, P.O.Box 16635-148, Tehran, Iran.
Embryonic development during the preimplantation stages is highly sensitive and critically dependent on the reception of signaling cues. The precise coordination of diverse pathways and signaling factors is essential for successful embryonic progression. Even minor disruptions in these factors can result in physiological dysfunction, fetal malformations, or embryonic arrest.
View Article and Find Full Text PDFInt J Dev Biol
December 2024
Department of Embryology, Institute of Developmental Biology and Biomedical Sciences, Faculty of Biology, University of Warsaw, Warsaw, Poland.
Aggregates of two mouse embryos produce viable offspring of normal size, indicating that there are mechanisms in the embryo that can downregulate their size to the size of the corresponding normal (single) embryos. Very little is known about the mechanisms controlling compensation for increased preimplantation size. Also, it is still elusive when exactly during development chimeric embryos regulate their size.
View Article and Find Full Text PDFFront Endocrinol (Lausanne)
December 2024
Reproductive Center of Integrated Medicine, The Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China.
Background: The blastocyst-stage embryo has been considered more advantageous for increasing the cumulative live birth rate (CLBR) at fresh embryo transfer (ET) compared to the cleavage-stage embryo. However, it remains uncertain whether this advantage extends to specialized subpopulations, such as women with thin endometrium (TE), who are characteristic of impaired endometrial receptivity. Thus, this study aims to evaluate the difference in the CLBR between cleavage-stage and blastocyst-stage embryos at fresh ET specifically in women with TE.
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