Researchers at the Federal University of Pelotas in Brazil have evaluated a technique to determine fetal sex in horses using circulating cell-free fetal DNA. This technique has been used in humans, but it was not known whether it would be reliable in horses.
Using 20 Thoroughbred mares in the last three month of pregnancy, the researchers isolated circulating cell-free fetal DNA in the mares’ plasma. They then used a polymerase chain reaction (PCR) assay to determine the sex of each fetus by confirming the presence (indicating a male) or absence (indicating a female) of the Y chromosome.
In the next stage of the study, they expanded the DNA by reamplification and performed a second PCR assay, again looking for the Y chromosome to indicate fetal sex.
After the mares foaled, comparisons were made between predicted and actual sex of the foals. The first PCR assay determination was accurate in 85% of foals, and using the results of the second PCR assay, a 95% correct prediction rate was achieved.
The Brazilian team’s next goal is to evaluate the test’s sensitivity earlier in the course of a pregnancy. If circulating cell-free fetal DNA can be found earlier, it might be used to predict
genetic diseases at a stage where affected fetuses could be eliminated, potentially saving a breeding season and avoiding the production of a diseased foal.
Fonte: By Kentucky Equine Research Staff · December 17, 2012