Mars is now marketing a canine genetic diversity test that they call "Optimal Selection". Apparently they were promoting this at Westminster KC. You send in blood samples from your bitch and prospective mates and they will tell you which mating would likely promote more heterozygosity (rather than having identical copies of the same chromosomes paired up in the offspring). Heterozygosity is a good thing from the standpoint of better general health and a stronger immune system in comparison to dogs with much homozygosity (that's when paired genes are identical rather than different).
There are cases in some breeds where a problematic, disease causing gene is suspected to be located on a specific chromosome. With the identification of different variations of the same chromosome, you can select mates with an eye to avoiding that certain suspicious chromosome, or at least avoid doubling up on it. Really interesting where science is taking us!