This study was conducted to investigate linkage disequilibrium (LD), historical effective population size (N_e) and haplotype block structures in genomes of highly selected Polish Arabian (AR; n=124) horses and conserved horse breeds derived from Polish native breeds, in particular, Malopolski (MLP; n=56), Sokolski (SOK; n=107), Sztumski (SZTUM; n=69), Hucul (HC; n=116) and Polish Konik (KN; n=99) horses, based on single nucleotide polymorphisms (SNPs) from the Neogen Equine Community BeadChip assay (Illumina, San Diego, CA). LD analysis was performed based on the pairwise r² statistic of SNPs at a distance up to 5Mb. At a short distance, up to 100kb, the lower average r² was observed in SOK (0.09) and SZTUM (0.10) breeds, representing draft horse type, and the highest average r² was observed in AR (0.19) and MLP (0.17) breeds, representing light horse type. At a distance of 4-5Mb, the average values of r² were 0.03 for HC and KN, 0.02 for AR and MLP and 0.01 for SOK and SZTUM. About 100 generations ago, effective population size (N_e) ranged from 518 (SOK) to 310 (AR) and five generations ago from 85 (SOK) to 40 (HC). A total of 6,162 (AR), 5,792 (MLP), 5,744 (HC), 5,429 (KN), 5,542 (SOK) and 4,848 (SZTUM) haplotype block structures, spanning 656.2Mb (AR), 439.4Mb (MLP), 381.2Mb (HC), 344.3 (KN), 206.7 (SOK) and 171.0Mb (SZTUM) of the genome were detected. Mean block lengths were estimated as 106.5±138kb, 75.9±120kb, 66.4±109kb, 63.4±109kb, 37.3±80kb and 35.3±81kb for AR, MLP, HC, KN, SOK and SZTUM, respectively. A visible similarity in the decay of LD across the genome, as well as in trends of historical N_e, were found for breeds representing the same horse type. Differences in the span of haplotype block structures were found between AR and Polish native horse breeds, which may reflect different demographic population histories and differences in intensity of selection.

进行这项研究的目的是研究波兰的高度精选波兰阿拉伯（AR; n = 124）马和源自波兰本地品种的保守马品种的基因组中的连锁不平衡（LD），历史有效种群大小（N _e）和单倍型块结构。特别是基于Malopolski（MLP; n = 56），Sokolski（SOK; n = 107），Sztumski（SZTUM; n = 69），Hucul（HC; n = 116）和Polish Konik（KN; n = 99）马Neogen Equine社区BeadChip分析（Illumina，圣地亚哥，加利福尼亚）中的单核苷酸多态性（SNP）分析。LD分析是基于SNP的成对r ²统计量进行的，最远距离为5Mb。在短距离内（最大100kb），较低的平均r ²在SOK（0.09）和SZTUM（0.10）品种中观察到代表草马类型，在AR（0.19）和MLP（0.17）品种中代表轻马类型，观察到最高的平均r ²。在4-5Mb的距离处，r ²的平均值对于HC和KN为0.03，对于AR和MLP为0.02，对于SOK和SZTUM为0.01。大约100代前的有效人口规模（N _e）的范围从518（SOK）到310（AR），五代前从85（SOK）到40（HC）。共有6,162（AR），5,792（MLP），5,744（HC），5,429（KN），5,542（SOK）和4,848（SZTUM）单倍型块结构，涵盖656.2Mb（AR），439.4Mb（MLP），381.2检测到基因组的Mb（HC），344.3（KN），206.7（SOK）和171.0Mb（SZTUM）。对于AR，MLP，HC，KN，SOK和SZTUM，平均块长度估计分别为106.5±138kb，75.9±120kb，66.4±109kb，63.4±109kb，37.3±80kb和35.3±81kb。整个基因组中LD的衰变以及历史N _e的趋势都具有明显的相似性_，被发现代表相同马类型的品种。在AR和波兰本地马种之间发现了单倍型块结构跨度的差异，这可能反映了不同的人口种群历史和选择强度的差异。