A structural variant in the 5'-flanking region of the TWIST2 gene affects melanocyte development in belted cattle

PLoS One. 2017 Jun 28;12(6):e0180170. doi: 10.1371/journal.pone.0180170. eCollection 2017.


Belted cattle have a circular belt of unpigmented hair and skin around their midsection. The belt is inherited as a monogenic autosomal dominant trait. We mapped the causative variant to a 37 kb segment on bovine chromosome 3. Whole genome sequence data of 2 belted and 130 control cattle yielded only one private genetic variant in the critical interval in the two belted animals. The belt-associated variant was a copy number variant (CNV) involving the quadruplication of a 6 kb non-coding sequence located approximately 16 kb upstream of the TWIST2 gene. Increased copy numbers at this CNV were strongly associated with the belt phenotype in a cohort of 333 cases and 1322 controls. We hypothesized that the CNV causes aberrant expression of TWIST2 during neural crest development, which might negatively affect melanoblasts. Functional studies showed that ectopic expression of bovine TWIST2 in neural crest in transgenic zebrafish led to a decrease in melanocyte numbers. Our results thus implicate an unsuspected involvement of TWIST2 in regulating pigmentation and reveal a non-coding CNV underlying a captivating Mendelian character.

MeSH terms

  • 5' Flanking Region / genetics*
  • 5' Flanking Region / physiology
  • Animals
  • Animals, Genetically Modified / genetics
  • Cattle / genetics*
  • Cattle / growth & development
  • DNA Copy Number Variations / genetics*
  • DNA Copy Number Variations / physiology
  • Female
  • Male
  • Melanocytes / physiology*
  • Phenotype
  • Polymerase Chain Reaction
  • Skin Pigmentation / genetics
  • Twist-Related Protein 2 / genetics*
  • Twist-Related Protein 2 / physiology
  • Zebrafish / genetics


  • Twist-Related Protein 2

Grant support

N.A.M. and T.L. were supported by SNF Project 31003A_149313. M.S. and N.M. were supported by SNF Project 31003A_15972. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.