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., 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 49:636-640, 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