Identification of Caprine <i>KRTAP28-1</i> and Its Effect on Cashmere Fiber Diameter

• Main Authors: Jiqing Wang, Huitong Zhou, Jon G. H. Hickford, Mengli Zhao, Hua Gong, Zhiyun Hao, Jiyuan Shen, Jiang Hu, Xiu Liu, Shaobin Li, Yuzhu Luo
• Format: Article
• Language: English
• Published: MDPI AG 2020-01-01
• Series: Genes
• Subjects: goat; keratin-associated protein 28-1 gene (<i>krtap28-1</i>); variation; cashmere fiber diameter
• Online Access: https://www.mdpi.com/2073-4425/11/2/121

The keratin-associated proteins (KAPs) are constituents of cashmere fibers and variation in many KAP genes (<i>KRTAPs</i>) has been found to be associated with fiber traits. The gene encoding the high-sulphur KAP28-1 has been described in sheep, but it has not been identified in the goat genome. In this study, a 255-bp open reading frame on goat chromosome 1 was identified using a search of similar sequence to ovine <i>KRTAP28-1</i>, and that would if transcribed and translated encode a high sulphur KAP. Based on the analysis of polymerase chain reaction amplicons for the goat nucleotide sequences in 385 Longdong cashmere goats in China, five unique banding patterns were detected using single strand conformation polymorphism analysis. These represented five DNA sequences (named variants <i>A</i> to <i>E</i>) and they had the highest resemblance to <i>KRTAP28-1</i> sequences from sheep, suggesting <i>A</i>&#8722;<i>E</i> are variants of caprine <i>KRTAP28-1</i>. DNA sequencing revealed a 2 or 4-bp deletion and eleven nucleotide sequence differences, including four non-synonymous substitutions. Of the four common variants (<i>A</i>, <i>B</i>, <i>C</i> and <i>D</i>) found in these goats, the presence of variant <i>A</i> was associated with decreased mean fiber diameter and this effect appeared to be additive. These results indicate that caprine <i>KRTAP28-1</i> variation might have value as a molecular marker for reducing cashmere mean fiber diameter.