Dog crossbreed major registry as purebred breeds. However, as of 2006, the portmanteau words cockapoo and Labradoodle are found in some dictionaries. Fanciful label names such as these are often found in for-sale ads, or on the websites that allow sellers to make up their own names for litters of crossbred puppies. The terms are only loosely descriptive and are seldom consistent. Among the trendier crossbreed dog are Labradoodles and Cockapoos, which each have their own fancier associations and affinity groups. Poodle and pug crossbreeds are also popular. In 2012, a new designer cross emerged called the Pomsky, which is a cross
Dog crossbreed the purebred breeds, while retaining their more appealing traits. Jon Mooallem in "The New York Times" writes, "Given the roughly 350 inherited disorders littering the dog genome, crossing two purebreds and expanding their gene pools can be 'a phenomenally good idea,' according to one canine geneticist—if it is done conscientiously." Crossbreeding has not been well studied in dogs, although it has been for livestock. The heritability of the desired trait being bred for (such as a hypoallergenic coat) needs to be known; "Heritability is the proportion of the measurable difference observed between animals for a given trait that is due