OMIA 002377-8845 : Knob, basal in Anser cygnoides

Possibly relevant human trait(s) and/or gene(s) (MIM number): 601413 (gene)

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal

Considered a defect: no

Key variant known: yes

Year key variant first reported: 2021

Cross-species summary: The basal knob is a prominent bump, swelling, bulge, or projection at the base of a bird's upper bill.

Species-specific description: Deng et al. (2021): "integrated radiographic, histological, transcriptomic and genomic analyses revealed the histomorphological characteristics and genetic mechanism of goose knob. ... integrated transcriptomic and genomic analysis contributed to the identification of 17 and 21 candidate genes associated with the knob formation in the skin and bone, respectively. Of them, DIO2 gene could play a pivotal role in determining the knob phenotype in geese. .... a non-synonymous mutation (c.642,923 G > A, P265L) changed DIO2 protein secondary structure in knob geese, and Sanger sequencing further showed that the AA genotype was identified in the population of knob geese ..."

Breeds: Lion Head, Sichuan White.

Associated gene:

Symbol Description Species Chr Location OMIA gene details page Other Links
DIO2 deiodinase, iodothyronine, type II Anser cygnoides domesticus - no genomic information (-..-) DIO2 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.

Since October 2021, OMIA includes a semiautomated lift-over pipeline to facilitate updates of genomic positions to a recent reference genome position. These changes to genomic positions are not always reflected in the ‘acknowledgements’ or ‘verbal description’ fields in this table.

OMIA Variant ID Breed(s) Variant Phenotype Gene Allele Type of Variant Source of Genetic Variant Reference Sequence Chr. g. or m. c. or n. p. Verbal Description EVA ID Inferred EVA rsID Year Published PubMed ID(s) Acknowledgements
1335 Lion Head Sichuan White Knob, basal DIO2 missense Naturally occurring variant AnsCyg_PRJNA183603_v1.0 NW_013185827.1 g.642923G>A p.(P265L) 2021 34193033


2021 Deng, Y., Hu, S., Luo, C., Ouyang, Q., Li, L., Ma, J., Lin, Z., Chen, J., Liu, H., Hu, J., Chen, G., Shu, D., Pan, Y., Hu, B., He, H., Qu, H., Wang, J. :
Integrative analysis of histomorphology, transcriptome and whole genome resequencing identified DIO2 gene as a crucial gene for the protuberant knob located on forehead in geese. BMC Genomics 22:487, 2021. Pubmed reference: 34193033. DOI: 10.1186/s12864-021-07822-9.

Edit History

  • Created by Imke Tammen2 on 11 Aug 2021
  • Changed by Imke Tammen2 on 21 Sep 2021