Note: / Studies suggest that chromosomal abnormalities notably mosaicism consisting of normal and abnormal cells is a common feature observed in mammalian preimplantation embryos. The data on chromosome abnormalities in bovine embryos however, are limited. The principal aim of this study was to investigate chromosome abnormalities and their effect on the development of bovine embryos produced in vitro. 193 embryos were evaluated for chromosomal abnormalities, using dual fluorescent in situ hybridization (FISH) with developed DNA probes for X and Y chromosomes. Our results demonstrate that uniformly abnormal embryos were found mostly at the early cleavage stages, and embryos with extensive chromosome abnormalities were usually arrested by the morula stage. Chromosomal mosaicism was observed at the 2- cell stage and increased steadily with subsequent stages of development. By the blastocyst stage, chromosomal mosaicism was the main abnormality observed and affected 95% of the blastocysts. Most of the mosaic blastocysts comprised of diploid and tetraploid cells. In the second part, a detailed analysis of 121 day 7 and days 9-10 blastocysts, demonstrated that the proportion of polyploid cells in most of the morphologically good quality embryos was less than 15%, which was significantly lower than in poor quality embryos. [...] / II a ete suggere que des anomalies chromosomiques particulierement le mosaicism sont frequemment rencontres chez les embryons des bovins produit in vitro, cependant les donnees disponibles sont tres limitees. Le but principal de cette etude est d'evaluer les anomalies chromosomiques particulierement le mosaicism au different stades de developpement embryonnaire par FISH en utilisant des probes 'ADN pour les chromosomes X et Y. Nos resultats demontrent que des embryons uniformement anormales ont ete surtout trouves aux premiers stades de cleavage, temoignant que les embryons avec une vaste anomalie affectant la totalite des embryons sont souvent arretes au stade du morula. Le mosaicism chromosomique a ete rencontre dans tous les stades de developpement et il a augmente emarquablement pendant le developpement embryonnaire. Ainsi, au stade du blastocyst, le mosaicism chromosomique etait l'anomalie principale observee avec 95 % de blastocysts analyses devenant mosaiques. [...]
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.111790 |
| Date | January 2004 |
| Creators | Ben Amor, Hanene |
| Contributors | Ao, Asangla (Supervisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science. (Department of Human Genetics.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 003924447, Theses scanned by McGill Library |
Page generated in 0.0019 seconds