Status of oocytes and embryos of X-autosome translocation carrier sows.
The impact of an X-autosome translocation t(Xp+; 14q-), on ovulation, fertilization and embryo survival in carrier sows, was examined and compared with these parameters of normal sows. Corpora lutea counts during week-2 and week-4 of gestation were similar in normal and carrier sows (14.4 +/- 1.36 and 15.5 +/- 2.18) although embryo recovery (11.0 +/- 1.87 and 6.0 +/- 1.47) was lower than that from normal sows (12.8 +/- 1.46 and 11.5 +/- 0.87), at these stages. Among the embryos karyotyped from the week-2 embryos of carrier sows, 42% were normal, 26.4% were carriers and 31.6% were of unbalanced chromosome make-up, and of the week-4 embryos of carriers, 33.3% were normal, 57.1% were carriers and 9.1% were chromosomally unbalanced females. The preponderance of females among the unbalanced embryos recovered at week-2 of gestation (11_ and 1_) and the total absence of males among those recovered at week-4, suggest that oocytes with unbalanced chromosome constitution are eliminated before week-2 of gestation if they are fertilized by Y bearing sperm, and that the unbalanced oocytes fertilized by X bearing sperm survive up to the peri-attachment stage even though all chromosomally unbalanced embryos are eliminated before term regardless of their sex.
Neal
M S
MS
Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Canada.
Reyes
E R
ER
King
W A
WA
Basrur
P K
PK
D000818:Animals; D020964:Embryo Loss / Q000235:genetics*; D005260:Female; D005306:Fertilization / Q000235:genetics*; D006580:Genetic Carrier Screening; D008540:Meiosis / Q000235:genetics; D010060:Ovulation / Q000235:genetics*; D013552:Swine / Q000235:genetics* / Q000502:physiology; D014178:Translocation, Genetic; D014960:X Chromosome / Q000235:genetics*