OMIA 001528-9940 : Fleece variation (woolly vs hairy) in Ovis aries

In other species: alpaca

Mendelian trait/disorder: yes

Considered a defect: no

Key variant known: yes

Year key variant first reported: 2017

Mapping: By conducting a GWAS on half-sib families of the Romane breed, involving "two thousands lambs produced from ten unrelated rams", Demars et al. (2017) identified two QTL for fleece variation (woolly vs hairy) on chromosomes OAR13 and 25. Fine-mapping of the latter (larger-effect) QTL narrowed its location to "72 kb (7,435,557–7,508,217 bp".

Molecular basis: Following whole-genome sequencing of "seven selected individuals carrying either the “Q” ancestral hairy allele (Romanov, n = 2), the “q” modern woolly allele (Berrichon du Cher, n = 3) or both (heterozygous QTL sires, n = 2)", Demars et al. (2017) narrowed 18 variants within the candidate region down to one likely causal variant: "the "woolly" allele results from the insertion of an antisense EIF2S2 retrogene (called asEIF2S2) into the 3' UTR of the IRF2BP2 gene leading to an abnormal IRF2BP2 transcript". Demars et al. (2017) reported that this IRF2BP2^asEIF2S2 allele variant "segregated perfectly with the QTLOar25 status for the 8 QTL rams since heterozygous sires were heterozygous for the insertion and homozygous rams were homozygous for the mutated IRF2BP2^asEIF2S2 allele". These same authors also provided "evidence that this chimeric IRF2BP2/asEIF2S2 messenger 1) targets the genuine sense EIF2S2 RNA and 2) creates a long endogenous double-stranded RNA which alters the expression of both EIF2S2 and IRF2BP2 mRNA. This represents a unique example of a phenotype arising via a RNA-RNA hybrid, itself generated through a retroposition mechanism".

Breed: Romane.

Associated gene:

Symbol Description Species Chr Location OMIA gene details page Other Links
IRF2BP2 interferon regulatory factor 2 binding protein 2 Ovis aries 25 NC_040276.1 (7071785..7067974) IRF2BP2 Homologene, Ensembl, NCBI gene


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WARNING! Inclusion of a variant in this table does not automatically mean that it should be used for DNA testing. Anyone contemplating the use of any of these variants for DNA testing should examine critically the relevant evidence (especially in breeds other than the breed in which the variant was first described). If it is decided to proceed, the location and orientation of the variant sequence should be checked very carefully.

Breed(s) Variant Phenotype Gene Allele Type of Variant Reference Sequence Chr. g. or m. c. or n. p. Verbal Description EVA ID Year Published PubMed ID(s) Acknowledgements
Romane Fleece variation, woolly IRF2BP2 insertion, gross (>20) Oarv3.1 25 2017 28379502


2017 Demars, J., Cano, M., Drouilhet, L., Plisson-Petit, F., Bardou, P., Fabre, S., Servin, B., Sarry, J., Woloszyn, F., Mulsant, P., Foulquier, D., Carrière, F., Aletru, M., Rodde, N., Cauet, S., Bouchez, O., Pirson, M., Tosser-Klopp, G., Allain, D. :
Genome-Wide Identification of the Mutation Underlying Fleece Variation and Discriminating Ancestral Hairy Species from Modern Woolly Sheep. Mol Biol Evol 34:1722-1729, 2017. Pubmed reference: 28379502. DOI: 10.1093/molbev/msx114.

Edit History

  • Created by Frank Nicholas on 01 Sep 2017
  • Changed by Frank Nicholas on 01 Sep 2017