Population structure analysis of eight goat breeds based on super-genotyping-by-sequencing

China harbors rich indigenous goat resources. However, factors such as the introduction of exotic breeds and crossbreeding have led to a decline in local populations and obscured genetic structures. Consequently, it is imperative to conduct genetic diversity and population structure assessments of key indigenous goat populations. This study employed Super-GBS sequencing technology to evaluate genetic diversity and population structure in eight goat breeds (n = 211), and further identified candidate genes associated with production traits and environmental adaptation through selection signature analysis. Ziwuling black goat (ZWL) exhibited the highest diversity, whereas Dazu black goat (DZH) showed the lowest. Pairwise F_ST revealed strong differentiation between DZH and Liaoning cashmere / Inner Mongolia cashmere goat (NMC) (0.1221) due to geographic isolation, but negligible divergence between Ziwuling cashmere (ZWLH) and Hexi cashmere (HXC) (0.0066), indicating gene flow. Population structure resolved three clades: DZH as an independent lineage, Yimeng black goat (YMH) clustering with ZWL, and multiple cashmere subgroups. Runs of homozygosity (ROH) revealed elevated inbreeding in DZH (F_ROH = 0.178) versus lower levels in cashmere breeds (0.071-0.098). Selective sweeps identified 252 genes linked to cashmere traits, including DCN, SEMA3D, FGF5, enriched in TGF-β, MAPK, and circadian rhythm pathways regulating hair follicle cycling. Comparative scans between arid-adapted NMC and subtropical DZH identified 372 genes (e.g., MTOR, ROBO2, PPP3CA) involved in thermogenesis, water reabsorption, and hypoxia response. Together, these findings highlight how artificial selection and environmental adaptation jointly shape goat genomic architecture. Conservation should prioritize populations with declining diversity (e.g., ZWLH, SXC) and implement controlled breeding to reduce inbreeding, thereby safeguarding agro-biodiversity and sustainable utilization.