Worm Breeder's Gazette 11(2): 84
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.
We have previously shown that duplications spontaneously break and produce new duplications at frequencies ranging between 10+E-4 and 10+E-5 (CSH abstracts 1989 p. 203). We have complementation tested a set of these duplications which break between unc-11 and dpy-14 to mutations in the region. A map of the results is shown in A and B. The spontaneous duplications are indicated by an asterisk. The arrangement of the markers is based on all the duplications except those derived from hDp23. With the exception of him-1 (see accompanying note), there has been no conflicting results. Duplications derived from hDp4 and hDp23 are unique in that they have multiple deletions. The other spontaneous duplications represent terminal deletions. hDp4 was derived from sDp2 by gamma irradiation. hDp78 is a spontaneous derivative of hDp4. hDp78 has three deletions with respect to hDp4, a deletion around unc-57, another around spe-11 and the third in the dpy-14 region. A single deletion event could produce both the unc-57 and dpy-14 deletions if hDp4 was a ring chromosome. The precedence for this conclusion comes from the analysis of eDp6 by Hunter and Wood (Gazette 10(2): 150). To explain the occurrence of three deletions, however, we must superimpose an inversion on the ring chromosome as shown in Figure C. [See Figure 1] hDp23 was a spontaneous derivative of hDp3. The four derivatives of hDp23, hDp26, 27, 30 and hDp59, all have complex structures (Fig. A and B). All of the duplications have a deletion around unc-63 that does not include let-359. Two of the duplications still carry spe-11 ( +) and hDp30 also has a dpy-14 deletion. This complex structure may reflect an unusual structure of hDp23 but unlike hDp4, we have not been able to derive a structure consistent with the results. The mapping data from all of our gamma induced duplications has been consistent. While most of our spontaneous duplications are also consistent in mapping experiments, we stress the importance of using caution when interpreting the mapping data derived from spontaneous duplications (see also accompanying note ). [See Figure 2]