http://www.aqha.com/  American Quarter Horse Association

http://www.allbreedpedigree.com/  All breed pedigree

http://www.animalgenetics.us/Equine/CCalculator1.asp Animal Genetics 

http://horsesonly.com/crossroads/xfactor/heart-1.htm
Great article on the large heart gene and how the X and Y chromosome plays in.

​Link to American Stock Dog Registry:
http://www.americanstockdog.org/index.php?page=breeds