Cytogenetical studies in mammalian preimplantaion embryos treated by biotechnology
1999
Yoshizawa, M. (Utsunomiya Univ. (Japan). Coll. of Agriculture)
Cytogenetical studies have not been accomplished enough in preimplantation embryos of mammals except humans. Because economical efficiency was considered to be the highest priority in domestic animals, abnormal animals were culled without cytogenetical diagnosis. Chromosomal aberration was not recognized as a genetic disease to be noticed. It was also the other reason that to make chromosome preparations from preimplantation embryos and to analyze the chromosomal normality are the difficult and laborious works. Nowadays, however, necessity of diagnosis for cytogenetical normalities in gametes or embryos becomes known to us for appearance of valuable individuals produced by biotechnology and improvement of conception rates in embryo transfer. The objective of the present studies was to establish cytogenetical data on embryos treated by biotechnology and to offer the data for improvement of biotechnology. The present studies introduced new methods for chromosome preparation of preimplantation embryos and other technical improvements on cytogenetical experiments. Incidences of chromosomal aberrations were higher in embryos derived from IVF than in those in vivo. The incidences and types of chromosomal aberrations differed in animal species, developmental stages of embryos, and the techniques used. Furthermore, the primary sex ratios were shown with high sexing rates.
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