ScienceAsia 26 (2000) : 009-013 |doi: 10.2306/scienceasia1513-1874.2000.26.009
Sex Determination by Polymerase Chain Reaction and
Karyotyping of Bovine Embryos at First Cleavage in vitro
Yindee Kitiyananta,b, Jumnian Saikhunb, Boripat Siriaroonratb and Kanok Pavasuthipaisita,b *
ABSTRACT: The purpose of this study was to compare the embryo sexing methods between PCR and
karyotyping of in vitro produced (IVP) bovine embryos at the 2-cell stage. The embryos were divided
into 3 groups according to the time of first cleavage completion. Zygotes cleaving before 24 hours
postinsemination (hpi), during 24-36 hpi and after 36 hpi were classified as fast, intermediate and slow
cleaving embryos, respectively. All 2-cell stage bovine embryos were separated into two blastomeres,
one was karyotyped and the other was subjected to PCR amplification. The percentages of embryos
which were sexed by PCR were significantly (p0.005) higher than those analyzed by karyotyping
(100% vs 56%). The proportions of male embryos sexed by PCR and karyotyping in the fast and
intermediate cleaving groups were significantly (p0.05) higher than female embryos, whereas the
proportions of males were significantly (p0.05) lower in the slow cleaving group. The overall ratios of
males to females analyzed by both methods were significantly (p0.05) different from the expected
ratio of 1:1.
a Department of Anatomy, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand.
b Institute of Science and Technology for Research and Development, Mahidol University, Salaya, Nakorn Pathom, 73170, Thailand.
* Corresponding author: Fax: +66-2-441 1013 E-mail: email@example.com
Received 15 Jul 1999, Accepted 1 Oct 1999