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Distribution of conversion tracts

We determined the frequency of conversion for each of the 12 marker sites of walter. The highest frequency occurred at the marker position closest to where the gap was originated, and the frequencies fell off exponentially in both directions. The results are consistent with a gap-widening process in which each base is removed independently with probability x = 0.99855. This model yields the theoretical curve shown as a dotted line. The average length of conversion tracts was 1379 bp.

Reference:

• Gloor, G. B., N. A. Nassif, D. M. Johnson-Schlitz, C. R. Preston and W. R. Engels. 1991. Targeted gene replacement in Drosophila via P element-induced gap repair. Science 253:1110-1117.
  
  

Other conversion tract distrubutions

We also obtained conversion tract distrubutions for cases where nonhomologous DNA was present, where there were gaps at the template, and where the template was on the homolog. In addition, we found a very similar distribution of conversion tracts at an autosomal site (50C) using a template on the homolog and naturally-occuring RFLP markers.

References:

• Preston, C. R., J. A. Sved and W. R. Engels. 1996. Flanking duplications and deletions associated with P-induced male recombination in Drosophila. Genetics (in press): (More technical information on making flanking deletions by this method)
  
• Lankenau, D., V. Corces and W. R. Engels. 1996. Comparison of targeted gene replacement-frequencies in Drosophila at the forked and white loci. Mol. Cel. Biol. 16:3535-3544.
  
• Engels, W. R., C. R. Preston and D. M. Johnson-Schlitz. 1994. Long-range cis preference in DNA homology search extending over the length of a Drosophila chromosome. Science 263:1623-1625.
  
• Nassif, N. A., J. Penney, S. Pal, W. R. Engels and G. B. Gloor. 1994. Efficient copying of nonhomologous sequences from ectopic sites via P element-induced gap repair. Mol. Cell. Biol. 14:1613-1625.
  
• Johnson-Schlitz, D. M. and W. R. Engels. 1993. P element-induced interallelic gene conversion of insertions and deletions in Drosophila. Mol. Cell. Biol. 13:7006-7018.
  
• Gloor, G. B., C. R. Preston, D. M. Johnson-Schlitz, N. A. Nassif, R. W. Phillis, W. K. Benz, H. M. Robertson and W. R. Engels. 1993. Type I repressors of P element mobility. Genetics 135:81-95.
  
• Nassif, N. A. and W. R. Engels. 1993. DNA homology requirements for mitotic gap repair in Drosophila. Proc. Nat. Acad. Sci. USA 90:1262-1266.
  

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