P-element insertion into exon 6.

Small P-element insertion (629bp) in one exon.

629bp P-element insertion.

P-element insertion in 3' coding region.

P-element insertion in one exon.

Insertion of 629bp P-element into the coding region of w.

Insertion of a 0.6 kb P-element at map position -2.1 relative to the transcription start site of w.

P-element is deleted (from position 139 to 2416). Same insertion point as for w^hash-6 and w^hd81b9. Same insertion orientation as w^hash-6 but opposite to that of w^hash-12 and w^hd81b9.

P-element insertion map site (kb): -2.03; Origin = insertion of w^a copia; '-' values to left (telomere) end; '+' values to right (centromere) end.

Unstable, reverts to wild-type by P-element excision.

Generated using the Harwich strain.

Reversion rate in males is 0.0015 +/- 0.0007. Reversion rate is increased in combination with w^a and w¹¹¹⁸. High-frequency reversion does not occur when w^hd80k17 is placed opposite a deletion overlapping the insertion point, or when w^hd80k17 is homozygous. Reversion frequency of w^hd80k17 is reduced in In(1)sc^S1Lsc^8R+S (which carries w^a), in comparison to w^a, probably because of reduction in pairing between the homologous chromosomes. The presence of an ectopic w gene, P{CaSpeR-C47.1}17C, stimulates reversion of w^hd80k17.

Conversion events have been identified, transposase induced replacement of the inserted P-element with P{walter}.

Repair of the P-element induced break can be achieved by precise excision of the insertion and revertants obtained through oligonucleotide directed repair.

81 revertants were isolated as part of study of repair of double stranded DNA breaks.

In the presence of transposase the P-element sequence can be converted at a high frequency with DNA from a derivative allele (members of the "w^hd-F" and "w^hd-D" group).

Targetted transposition, one P-element exactly replaces another P-element, has been studied at the w locus. The donor transposon, P{walLy}, located in trans on the second chromosome, has been recovered in both orientations. Targetted transposition occurs at approximately the same rate as targetted gene conversion.

Precise excision of the P-element can be found at a rate hundreds of times greater if a homologous w sequence is present which does not contain the same P-element insertion. No precise loss is seen when no homologous w sequence or a w allele containing a deletion covering the insertion site is present on the homologous chromosome. This evidence suggests P-elements transpose via a cut and paste mechanism.

Template-dependent transposase mediated gene conversion of w^hd80k17 gives rise to four different classes of event. The most common are conversions external to the w^hd80k17 P-element and gene conversion internal to the P-element. Right-end and left-end duplications are also observed. These gene conversion experiments suggest that P-element excision occurs by a staggered cut that leaves at least 33bp of single-stranded sequence, and demonstrate that an efficient homology search is conducted by the broken end with less than 31 nucleotides.