In particular, biologists have suspected that the insects' progression to six legs, and the evolution and modification of arthropod appendages in general, are driven by changes in Hox gene activity.

Joshi et al. show that, in addition to forming base pair–specific hydrogen bonds in the DNA major groove, certain Hox proteins detect DNA shape in the minor groove. Figure 1: Cooperative binding ...

This precise transcribing of genes is handled by proteins known as transcription ... the fly's suite of Hox genes must be expressed in a precise way and at precise times. Gene switches such ...

A similar negative feedback system controlled by the HES protein family has also been observed ... of nearly all insects and vertebrates, the Hox genes play a role in identifying each segment ...