In an article published this week in Science Express, a retrotransposon was linked to stubby dog legs. Retrotransposons are transposons that are first transcribed into RNA, then reverse transcribed back to DNA before being re-inserted into the genome. Looking at more than 40,000 DNA markers to find genes associated with leg length in domestic dogs, NHGRI scientists found fibroblast growth factor 4 to be strongly associated with short legs in dogs, including the dachshund, corgi, and basset hound.