X-marks the spot and hidden treasures in Drosophila meiotic recombination patterning: unearthing the role of specialized sites in assuring and patterning crossovers

<p style="font-weight: 400;">Meiotic recombination patterning is thought to be dependent on the location of a crossover event on a chromosome and distance to other events. Chromosomal aberrations result in disruptions to recombination patterning, with lower recombination rates near translocation breakpoints (Hawley, 1980). This reduction in recombination is not distance dependent, and instead is confined to within the interval between the two nearest "Hawley Sites," with recombination rates returning to wild-type levels beyond these sites. <span style="font-weight: 400;">To investigate the nature of these Hawley Sites, we measured recombination using genetic marker screens in female flies heterozygous for deficiencies spanning the 11A Hawley Site (HS11). We found that flies carrying deficiencies that remove all or part of HS11 exhibit reduced recombination globally, a reduction not attributable to missing genetic material within deficiency boundaries. Flies carrying deficiencies which did not remove HS11 had slightly reduced recombination rates, a reduction attributable to missing genetic material within deficiency boundaries. These provide insight into the factors regulating recombination patterning.</span>