Cytological maps of lampbrush chromosomes of both parental species of Pelophylax esculentus complex. Working maps of all lampbrush chromosomes of P. ridibundus (a) and P. lessonae (b). Chromosomes were arranged and lettered according to their relative length. Comparative locations of the most conspicuous landmark structures colored according to their marker components are shown. Green color indicates accumulation of pre-mRNA splicing factors, red – coilin positive structures, yellow – accumulation of both splicing factors and coilin, blue – enrichment with nucleolus components.