UC Davis School of Veterinary Medicine Veterinary Genetics Laboratory


Pre-implantation genetic diagnosis (PGD) is a procedure used to screen embryos recovered after uterine flush to determine gender and genetic traits by DNA testing prior to implantation in the uterus.  DNA testing of horse embryos prior to implantation allows selection of those embryos that have desired sex, coat color variants, or that are free of known genetic diseases, thus maximizing the outcome of embryo transfer process.

The Veterinary Genetics Laboratory offers DNA tests on horse embryo biopsies for gender, genetic disease (GBED, HERDA, HYPP, Lethal White Overo, Malignant Hypothermia for Quarter Horses and related breeds, or  CA for Arabians) and coat color (Red Factor, Agouti, Champagne, Cream, Dun, Pearl, Silver, Lethal White Overo, Gray, Sabino-1, Tobiano, Dominant White W10, Splashed White).

Biopsies are performed on Day-6 or Day-7 blastocysts from which 5-10 trophoblast cells are harvested by suction. Cells are placed at the bottom of a 0.2 ml, thin walled tube in 1-2 microliters of PBS, 2% PVP buffer or other cell culture medium and frozen. The volume of medium is critical. Liquid in excess of 2 microliters negatively affects the process of whole genome amplification and may result in test failure. Tubes are shipped overnight on ice or dry ice via DHL, FedEx or UPS. Embryo biopsies are received Monday-Wednesday, with results available within 36 hrs.


Technical information on collection of horse embryo biopsies and DNA screening are available from:

Choi YH, Gustafson-Seabury A, Velez IC, Hartman DL, Bliss S, Riera FL, Roldán JE, Chowdhary B, Hinrichs K. Viability of equine embryos after puncture of the capsule and biopsy for preimplantation genetic diagnosis. Reproduction 140(6):893-902, 2010.

Y. H. Choi , M. C. T. Penedo, P. Daftari , I. C. Velez  and K. Hinrichs. Accuracy of pre-implantation genetic diagnosis using cells biopsied from equine blastocysts. Reproduction, Fertility and Development 24(1): 163-164, 2011.  http://dx.doi.org/10.1071/RDv24n1Ab102

Veterinary Genetics Laboratory, Tel 530-752-2211, Email VGL