Non-uniform chromosomal SNP density biases sites of meiotic crossovers in Drosophila melanogaster

Genetic mapping studies generally assume uniform crossover distribution across chromosomes. However, this study demonstrates that an uneven density of single nucleotide polymorphism (SNP) is associated with biased sites of meiotic recombination. Using brain dopamine-deficient Drosophila, SNP dense regions show reduced crossover frequency, which reduced the mapping resolution, complicating genetic trait localization. These findings highlight the need to consider parental chromosome SNP distribution and its impact on recombination when designing genetic mapping studies. Future studies should consider chromosome structure, parental haplotype, and sequence heterogeneity to enhance mapping accuracy and resolution.