Fig. 3

Transmission electron microscopy (TEM) cross-sections of bovine sperm flagella. Representative TEM cross-sections of sperm flagella at the mid-piece, principal piece and end piece in a control bull (a–c) and a bull homozygous for the 1-bp deletion in QRICH2 (d–m). Irregularities in the flagellar cross-sections from the homozygous bull prevent unambiguous assignment of the principal and end piece (g–m). The axonemes of most of the flagella lack some of the outer microtubules resulting in deviations from the typical arrangement of nine outer microtubule doublets surrounding the central pair in the homozygous bull. Cross-sections also show irregular assembly of axonemes and structures such as outer dense fibres that are supposed to enclose the axonemes (d, f). Scale bar: 200 nm