Accepted_test
Galliformes and Anseriformes represent two branches of the Galloanserae group. While Galliformes have been extensively studied, the evolution of Anseriformes karyotypes remains relatively understudied, with only a few species included in comparative genomic analyses. Therefore, this study aims to conduct comparative genomic analyses of the karyotypes of three representatives of the order Anseriformes from the Anatidae family: the mallard (Anas platyrhynchos), pintail (Anas acuta), and common goldeneye (Bucephala clangula). Analysis of the karyotypes were performed by routine staining and GTG, CBG, CDAG methods and revealed that all studied species possess the same diploid number of chromosomes (2n=80). However, the karyotype of the common goldeneye differs from those of representatives of the genus Anas due to an increased number of macrochromosomes and the presence of large blocks of heterochromatin on most macroautosomes and sex chromosomes. The utilization of stone curlew chromosome specific probes by fluorescence in situ hybridization revealed homologies on duck’s macro- and microchromosomes. Previous studies comparing chicken and stone curlew karyotypes facilitated the identification of homologies between chicken chromosomes and the karyotypes of the three duck species. Interspecific comparisons revealed that the increase in macrochromosome numbers in the common goldeneye karyotype is due to fissions in two ancestral elements. Clusters of rRNA genes were found on four pairs of pintail microchromosomes and on two pairs of common goldeneye microchromosomes. Our study demonstrated that Anatidae species possess microchromosomes enriched in telomeric sequences. All these findings contribute to understanding of the evolutionary transformations of macro- and sex chromosomes in Anseriformes.