Histology dataset supporting paper “ Massive detection of cryptic recessive genetic defects in dairy cattle mining millions of life histories”

<i>Light microscopy (LM).</i> Images LM_RFC5_Case1 to LM_RFC5_Case4 and LM_RFC5_Control1 to LM_RFC5_Control 4 were used to count the number of hair follicles in a randomly selected 1 mm2 square and to measure the diameter of the pilary canal of 50 adjacent hair follicles in shoulder skin samples from four Normand heifers homozygous for the RFC5 inframe deletion and four matched controls. Samples were fixed in 10% neutral buffered formalin for 24 h at +4°C, dehydrated in a graded ethanol series (30% to 100%), cleared in xylene and embedded in paraffin. Longitudinal microtome sections (5 µm, Leica RM2245) were mounted on adhesive slides (Klinipath-KP-PRINTER ADHESIVES), deparaffinised and stained with a Roan solution (nuclear fast red, orange G and aniline blue). Slides were digitised using Pannoramic Scan 150 and analysed using CaseViewer 2.4 software (3D Histech).In addition, images LM_RFC5_Case2 and LM_RFC5_Control 1 were used to prepare panels f and e of Figure 6, respectively.<i>Transmission Electron Microscopy (TEM). </i>Images TEM_NOA1_Case1 to TEM_NOA1_Case3 and TEM_NOA1_Control1 to TEM_NOA1_Control3 were obtained from left ventricular heart samples from three Montbeliarde heifers homozygous for the NOA1 frameshift variant and three matched controls. The samples were fixed with 2% glutaraldehyde in 0.1 M Na cacodylate buffer pH 7.2, for 4 hours at room temperature. They were then contrasted with Oolong Tea Extract (OTE) 0.2% in cacodylate buffer, postfixed with 1% osmium tetroxide containing 1.5% potassium cyanoferrate, dehydrated in a graded ethanol series (30% to 100%), and embedded in Epon, after the ethanol was gradually replaced by ethanol-Epon mixtures. Thin sections (70 nm) were collected on 200 mesh copper grids, and counterstained with lead citrate. The grids were examined on a Hitachi HT7700 electron microscope operated at 80kV (Milexia, France) and images were acquired using a charge-coupled device camera (AMT). The six images were used as part of the physiopathological characterisation of NOA1 loss of function. In addition, images TEM_NOA1_Case1 and TEM_NOA1_Control 1 were also used to prepare panels n and m of Figure 6, respectively.