Worm Breeder's Gazette 11(3): 54
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
In the last gazette we reported on the genetic mapping of spontaneously derived chromosome I duplications. Since this time, one of us (RER) has re-evaluated the complementation data and has proposed a more parsimonious map. In addition, unc-38 is now in a new position based on some data from this lab and from P. Mains (personal communication). The maps in Figures 1 and 2 summarize the new interpretations. The h duplications 26, 27, 30 and 59 are spontaneous unc-63(-) derivatives of hDp23. hDp23 was itself a spontaneous duplication derived from hDp7. hDp78 is a spontaneous derivative of hDp4. Since the last note, a new dpy5(-) derivative of hDp74, hDp100, was isolated in the lab by Shiv Prasad (Figure 1). In the old map, the gene order was let-375 let-359 (let-364 unc-63) (let-361 let-371 spe-11). According to the new interpretation, the gene order is let-375 (let-364 unc-63) let-359 spe-11(let-361 let-371) (Figure 2). [See Figure 1] All the spontaneous Dps (indicated in Figures 1 and 2 by an asterisk) are characterized by double, and sometimes triple, deletion events. The deletions often involve both ends of the progenitor duplications. For example, hDp30 results from a deletion of hDp23 involving both the dpy-14, unc-63 and let-363 regions. In the previous article we proposed a structure for hDp4 based on the structure of its derivative hDp78; which has deletions of the dpy-14, unc-57 and let-363 regions. The proposed structure for hDp4 is shown in Figure 3a and involves a ring chromosome with a superimposed inversion relative to the linear map. With the revised map shown here, we can now propose a similar structure for hDp23, and possibly hDp74, based on the structure of their derivatives. If hDp23, like the proposal for hDp4, is a ring chromosome with a superimposed inversions than the multiple deletions with respect to the linear map can be explained by a single deletion on the ring chromosome-inversion map. Figure 3b shows the proposed structure for hDp23 and the deletions which produced the four derivatives. [See Figures 2-3]
