Chromosome aberrations in in vitro-produced bovine embryos at days 2-5 post-insemination.
Availability of embryos of high quality is required to obtain satisfactory embryonic developmental rates and normal calves following transfer of in vitro-produced (IVP) bovine embryos. One relevant quality parameter is the frequency of chromosome aberrations, which can be evaluated using multicolor fluorescent in situ hybridization (FISH) with chromosome 6- and chromosome 7-specific probes in cattle. In this study, interphase nuclei (n = 3805) were analyzed from 426 bovine IVP embryos. We found that 73%, 72%, 81%, and 58% of the embryos from Days 2, 3, 4, and 5 post-insemination (pi), respectively, displayed a normal diploid chromosome number in all cells. When looking at the types of chromosome aberrations, the percentages of mixoploidy at Days 2, 3, 4, and 5 pi were 22%, 15%, 16%, and 42%, respectively, whereas the percentages of polyploidy (i.e., all nuclei in an embryo were analyzed and were polyploid) were 5%, 13%, 3%, and 0%, respectively. In conclusion, numerical chromosome aberrations were detected as early as Day 2 pi. The development of polyploid embryos is slow and is apparently arrested during the third cell cycle, whereas the mixoploid embryos seem to continue development.
Viuff
D
D
Department of Clinical Studies, Reproduction, Royal Veterinary and Agricultural University, DK-1870 Frederiksberg C, Denmark. dv@kvl.dk
Greve
T
T
Avery
B
B
Hyttel
P
P
Brockhoff
P B
PB
Thomsen
P D
PD
D000818:Animals; D001755:Blastocyst; D002417:Cattle; D002869:Chromosome Aberrations; D004622:Embryo, Mammalian / Q000502:physiology*; D005314:Embryonic and Fetal Development / Q000235:genetics; D005307:Fertilization in Vitro; D017404:In Situ Hybridization, Fluorescence; D011123:Polyploidy