OMIA 001952-9940 : Microtia in Ovis aries

In other species: pig

Possibly relevant human trait(s) and/or gene(s) (MIM number): 600674

Mendelian trait/disorder: unknown

Considered a defect: yes

Species-specific description: Hereditary underdevelopment of the ear

Mapping: Having genotyped 8 affected and 12 non-affected sheep each with the Illumina OvineSNP50® chip, Jawasreh et al. (2016) reported that "a single-locus analysis revealed a statistically significant association (P = 0.012, genome-wide) with a SNP at basepair 34 647 499 on OAR23. This marker is adjacent to the gene encoding transcription factor GATA-6, which has been shown to play a role in many developmental processes, including chondrogenesis. The lack of extended homozygosity in this region suggests a fairly ancient mutation, and the time of occurrence was estimated to be approximately 3000 years ago."

Mastrangelo et al. (2018) obtained a strong signal on a different chromosome: "A total of 40 individuals, 20 with microtia and 20 normal, were genotyped with the Illumina OvineSNP50 BeadChip. The comparison among the results from a genome-wide association study, Fisher's exact test and FST analysis revealed a single strong association signal: rs419889303 on chromosome 1, located within intron 3 of the CLRN1 gene. Our study suggests for the first time that this novel candidate gene is responsible for microtia in sheep."

Breed: Awassi.


Note: the references are listed in reverse chronological order (from the most recent year to the earliest year), and alphabetically by first author within a year.
2018 Mastrangelo, S., Sottile, G., Sutera, A.M., Di Gerlando, R., Tolone, M., Moscarelli, A., Sardina, M.T., Portolano, B. :
Genome-wide association study reveals the locus responsible for microtia in Valle del Belice sheep breed. Anim Genet :, 2018. Pubmed reference: 30160299. DOI: 10.1111/age.12719.
2016 Jawasreh, K., Boettcher, P.J., Stella, A. :
Genome-wide association scan suggests basis for microtia in Awassi sheep. Anim Genet 47:504-6, 2016. Pubmed reference: 26990958. DOI: 10.1111/age.12431.
2002 Porter, V. :
Mason's World Dictionary of Livestock Breeds, Types and Varieties. 5th edn. C.A.B International, Wallingford, UK. :, 2002.
1930 Lush, J.L. :
Earlessness in Karakul sheep Journal of Heredity 21:107-112, 1930.

Edit History

  • Created by Frank Nicholas on 26 Mar 2016
  • Changed by Frank Nicholas on 03 Sep 2018