Abstract Background The Y chromosome of Drosophila melanogaster harbors several genes required for male fertility. The genes for these fertility factors are very large in size and contain conspicuous amounts of repetitive DNA and transposons. Three of these loci (ks-1. kl-3 and kl-5) have the ability to develop giant lampbrush-like loops in primary spermatocytes. https://bbmbatteryes.shop/product-category/405/