The following partial restriction map shows a recombinant plasmid, pBIO220, formed by cloning a piece of Drosophila DNA (striped segment), including the gene rosy, into the vector pBR322, which also contains the penicillin resistance gene, pen. The vector part of the plasmid contains only the two E recognition sequences shown and no A or B sequences. The gel (in the next column) shows several restriction digests of pBIO220.

(a) Use the stained gel pattern to deduce where restriction-enzyme recognition sequences are located in the cloned fragment.

(b) A PCR-amplified copy of the entire 2000-bp rosy gene was used to probe a Southern blot of the same gel. Use the Southern blot results to deduce the location of rosy in the cloned fragment. Redraw the map showing the location of the rosy gene.