Butterfly eyespots are beautiful novel traits with an unknown developmental origin. Here we show that eyespots likely originated via co-option of the antennal gene-regulatory network (GRN) to novel locations on the wing. Using comparative transcriptome analysis, we show that eyespots cluster with antennae relative to multiple other tissues. Furthermore, three genes essential for eyespot development (Distal-less (Dll), spalt (sal), and Antennapedia (Antp)) share similar regulatory connections as those observed in the antennal GRN. CRISPR knockout of cis-regulatory elements (CREs) for Dll and sal led to the loss of eyespots and antennae, and also legs and wings, demonstrating that these CREs are highly pleiotropic. We conclude that eyespots likely re-used the ancient antennal GRN, a network previously implicated also in the development of legs and wings.

Cytomorphologic features in a series of fine-needle aspiration biopsies from eight patients with seminoma or dysgerminoma were reviewed, and the findings were further correlated with histopathologic and ultrastructural appearances. Three cell types were encountered. Type I was least differentiated and least frequent. Type II was most frequent and had well-developed cytoplasm rich in organelles. Type III was similar to type II but also contained abundant cytoplasmic glycogen. In cytology smears, type III cells contained large punched-out cytoplasmic vacuoles corresponding to the areas of glycogen deposition. The background contained a variable mixture of inflammatory cells including lymphocytes, plasma cells, epithelioid cells, and epithelioid granulomas. The significance of these findings in the diagnosis of seminoma or dysgerminoma and the distinction from other germ-cell and non-germ-cell tumors is briefly discussed.

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