How Teacup, Tinies, & Micro Yorkies Came to Be
As a breeder, I have seen all sizes and colors of Yorkies. One topic that seems to invoke strong opinions from all involved is the Teacup/ Tiny/ Micro Size Yorkies. While I do NOT purposely breed for the itty bitty ones, I do personally own 2 micro yorkies,Pieenie and Macaroni, and would not trade them for their world. (Pieene weighs 2.2 pounds, dripping wet and Macaroni weighs 2.5 lbs, full belly.) When Pieenie was born she was extremely small, so much so, my Vet gave me ‘the look’ and uttered those words no one wants to hear at the vet’s office….“You may need to prepare yourself.”
Well I decided then and there, I was NOT preparing for shit. [Sorry] This little one needed me to fight for her until she was strong enough to fight on her own, so I did. I carried her with me everywhere for the first 5 weeks of her life: bottling feeding, cleaning her tushie, burping her, everything. I devised a make-shift papoose out of an old toboggan and duct taped it between my boobs to keep her warm. Fast forward, Pieenie is 3 years old doing well, with no health issues. Point is this, some dogs are just small and now science is understanding why….
Scientists have discovered why small dogs are small. They have found a DNA sequence located on chromosome 15, which is next to the gene known as IGF1. This sequence was found in all dog breeds they tested that were 20 lbs. and under. The Yorkshire Terrier breed falls into this category. Dogs over 20 lbs have the IGF1 gene, but don’t have the DNA sequence located on chromosome 15.
The IGF1 gene produces a growth-inducing protein hormone. What they have found is that this DNA sequence that is located next to the IGF1 gene causes the IGF1 gene to produce less of the growth protein hormone. They also found in a study on Poodles, that the less of the growth hormone in their bloodstream the smaller the body size. They haven’t found the exact mutation in this DNA sequence which causes the reduced output of this growth hormone but they feel they are on the path to discover it.
Now you may be wondering what does this have to do with Yorkies? It actually gives a scientific explanation on why the really small Yorkies also known as teacup, micro, or miniature occur. Most of what you read on the internet implies that the smaller than average Yorkies are all small because they are just the runts of the litter and have underlying health issues. There is some truth to that statement in that if a Yorkie puppy has underlying health issues it probably will be smaller than usual. But a smaller than usual puppy does not mean the puppy has health issues.
The fact is a Teacup Yorkie can be smaller than usual because it has less of the growth hormone in its bloodstream or because it has underlying health issues. What we’ve seen as well as other breeders of the extra small Yorkshire Terriers is that somewhere around 8-12 weeks of age the puppy’s growth rate begins to dramatically slow down or STOP in Pieenie’s case. This could be an indication of reduced levels of the growth hormone in the bloodstream. Hopefully, someday there will be standard testing to determine the levels of this hormone in the bloodstream. You can read more about this in the article by JR Minkel on April 5, 2007 in SCIENTIFIC AMERICAN
Gene Makes Small Dogs Small: Small breeds share a gene variant that limits their growth
