Three types of sequence variations--single-nucleotide polymorphisms (SNPs), insertions and deletions (indels), and short tandem repeats (STRs)--have been extensively reported in mammalian genomes. In this study, we discovered a novel type of sequence variation, i.e., multiple-nucleotide length polymorphisms (MNLPs) in bovine UCN3 (Urocortin 3) and its receptor CRHR2 (corticotropin-releasing hor...