Figure 4.

Electron micrographs of sperm bundle testes from six genotypes. (A) Standard male with susceptible Y chromosome showing ∼128 normally developing spermatids. (B) Sex-ratio males with the susceptible Y chromosome (X^SRY^sus) show ∼64 normally developing spermatids and several that do not appear to have individualized. @, double spermatids; #, groups of spermatids that have failed to individualize, and ↑, axonemes without cytoplasm or nebenkern. (C and D) Sperm bundles from X^STY^res and X^SRY^res males appear similar to each other with ∼120 normally developing spermatids. *, either caudal ends of sperm tails or incompletely developed sperm tails and %, spermatids surrounded by vacuoles. (E) Sperm bundles from X^STO males, which look either normal or are almost completely void of normal spermatids (inset), and (F) sperm bundles from X^SRO males had no normally developing spermatids. Bars, 1 μm.