Couples could use prenatal testing to look for problematic genes on the X chromosome, for example. (sciencemag.org)
In fact, many breeds are crossed in a bid to cancel out some of the more problematic genes and the hybrid outcome ends up being more physically sound than their parents. (petguide.com)
Traditionally, geneticists have hunted down genes by tracking the inheritance of a genetic disease through large families or by searching for suspected problematic genes among patients. (science.sciencemag.org)