FIGURE 1.

CheB gene expression is almost exclusively sexually dimorphic and restricted to legs and wings, appendages enriched in gustatory hairs. A, Northern blot analysis of RNA extracted from appendages (antennae, legs, and wings) or heads (without antennae) from males or females. Radiolabeled probes are of similar size and specific activity, allowing for the approximate comparison of expression levels of different genes. B, semi-quantitative RT-PCR analysis of CheB gene expression. Expression of all 12 CheB genes in each body part was assessed semi-quantitatively (25). Relative expression levels in different tissues can be evaluated by comparing the ratio of the larger DNA product, amplified from intron-containing genomic DNA, to the smaller DNA product, resulting from amplification of the cDNA (23).