The Mean Staple Length of Wool Fibre Is Associated with Variation in the Ovine Keratin-Associated Protein 21-2 Gene

Wool and hair fibres consist of a variety of proteins, including the keratin-associated proteins (KAPs). In this study, a putative ovine homologue of the human KAP21-2 gene (KRTAP21-2) was identified. It was located on chromosome 1 as a 201-bp open reading frame (ORF) in the ovine genome assembly from a Texel sheep (v.4 NC_019458.2: nt122932727 to 122932927). A polymerase chain reaction- single strand conformation polymorphism (PCR-SSCP) analysis of this ORF, and subsequent DNA sequencing, identified five sequences (named A-E). The putative amino acid sequences that would be produced, shared some identity with each other and with other KAPs, but they were most similar to ovine KAP21-1, and phylogenetically related to human KAP21-2. The location of the ovine KRTAP21-2 sequence was consistent with the location of human KRTAP21-2, and this suggests they represent different variant forms of ovine KRTAP21-2. Variation in this gene was investigated in 389 Merino (sire) × Southdown-cross (ewe) lambs. These were derived from four independent sire-lines. The sequence variation was found to be associated with variation in five wool traits: including mean staple length (MSL), mean fibre diameter (MFD), fibre diameter standard deviation (FDSD), prickle factor (PF), and greasy fleece weight (GFW). The most persistent effect of KRTAP21-2 variation was with variation in MSL; with the MSL of sheep of genotype AC being 12.5% greater than those of genotype CE. A similar effect was observed from individual variant absence/presence models. This suggests that KRTAP21-2 should be further investigated as a possible gene-marker for improving MSL.

[1]  Huitong Zhou,et al.  Identification of the Ovine Keratin-Associated Protein 21-1 Gene and Its Association with Variation in Wool Traits , 2019, Animals.

[2]  Huitong Zhou,et al.  Associations between variation in the ovine high glycine-tyrosine keratin-associated protein gene KRTAP20-1 and wool traits. , 2018, Journal of animal science.

[3]  Huitong Zhou,et al.  A nucleotide substitution in the ovine KAP20-2 gene leads to a premature stop codon that affects wool fibre curvature. , 2018, Animal genetics.

[4]  Huitong Zhou,et al.  Identification of the Ovine Keratin-Associated Protein 26-1 Gene and Its Association with Variation in Wool Traits , 2017, Genes.

[5]  Huitong Zhou,et al.  Identification of the Ovine Keratin-Associated Protein 22-1 (KAP22-1) Gene and Its Effect on Wool Traits , 2017, Genes.

[6]  J. Dyer,et al.  Wool Keratin-Associated Protein Genes in Sheep—A Review , 2016, Genes.

[7]  Valer Gotea,et al.  The functional relevance of somatic synonymous mutations in melanoma and other cancers , 2015, Pigment cell & melanoma research.

[8]  Jolon M. Dyer,et al.  An Updated Nomenclature for Keratin-Associated Proteins (KAPs) , 2012, International journal of biological sciences.

[9]  J. Dyer,et al.  Identification of the ovine KAP11-1 gene (KRTAP11-1) and genetic variation in its coding sequence , 2011, Molecular Biology Reports.

[10]  Hong‐sheng Ouyang,et al.  Characterization of the structural and molecular defects in fibres and follicles of the merino felting lustre mutant , 2009, Experimental dermatology.

[11]  H. Zhou,et al.  An effective method for silver-staining DNA in large numbers of polyacrylamide gels. , 2009, Analytical biochemistry.

[12]  J. Hickford,et al.  A two-step procedure for extracting genomic DNA from dried blood spots on filter paper for polymerase chain reaction amplification. , 2006, Analytical biochemistry.

[13]  Michael A Rogers,et al.  Human KAP genes, only the half of it? Extensive size polymorphisms in hair keratin-associated protein genes. , 2005, The Journal of investigative dermatology.

[14]  H. Winter,et al.  Characterization of a First Domain of Human High Glycine-Tyrosine and High Sulfur Keratin-associated Protein (KAP) Genes on Chromosome 21q22.1* , 2002, The Journal of Biological Chemistry.

[15]  G. Rogers,et al.  The role of keratin proteins and their genes in the growth, structure and properties of hair. , 1997, EXS.

[16]  J. Gillespie.  The Proteins of Hair and Other Hard α-Keratins , 1990 .