Fig. 4

A newly identified s-ITS in exon of Gtl2. a The repetitive sequence of the Gtl2 gene showed typical features of short interstitial telomeric sequences (sITSs). The short sequence in red font is telomere DNA, and the sequence in blue font is the hairpin structure. b Genotyping of the repeat element (RE) mutation in DNA extracted from skin tissue of different sheep breeds. (I) Genotypes of the RE mutations of Tan sheep (ALC wool), Ujimqin sheep (ALC wool), ALC (ALC wool), MF (MF wool), and Merinos (MF wool). (II) RE genotypes of Small Tail Han sheep (ALC wool). (III) RE genotypes in Merino sheep (MF wool). (IV) Allele types of REs identified using sub-PCR. The four alleles were sequenced as shown below. M: Marker. Repeat sequence units are represented in a large, bold font. The number of repetitions of the base unit is shown as the numbers in the lower right of the repeating unit (below). Primers are listed in Additional file 2: Table S5, named “CNV identification_1.” ① to ④ indicate the different copy number of s-ITS in one allele, specifically, it represents the number of copies from 4 to 7. c CNV analysis of sITSs in reciprocal cross families. Primers are listed in Additional file 2: Table S5, named “CNV identification_2.” The yellow lettering in the diagram represents ear tag of sheep, where ALC indicates the ancestral-like coarse wool sheep. d Multiple alternative splicing of the Gtl2 gene was detected using polyacrylamide gel electrophoresis; the primers are shown in Additional file 2: Table S5 and named “CNV identification_1.”, the yellow lettering in the diagram represents ear tag of sheep, where ALC indicates the ancestral-like coarse wool sheep. e The generation process pattern of sITS-miRNA in the Gtl2-miRNA locus. G, DNAMAN multiple sequence alignment analysis was used to analyze the result of Sanger Sequencing for three adjacent alternative splicing of the Gtl2-sITS site. f The comparative analysis of sITS-miRNA expression using miRNA-seq data (*, 0.01 < P < 0.05). g Comparative analysis of sITS-miRNA expression in ALC and MF wool lambskin tissue at P1 (n = 5) and P30 (n = 3). (***P < 0.001)