[Comparison of the genome of the alligator gar with the genomes of several other fish].

Hybridization of alligator gar (Lepisosteus osseus, Lepisosteiformes, Ganoidomorpha) [125I]- or [3H]DNA fractions with DNAs of more or less phylogenetically related fishes was studied. Almost all of the repeated and unique sequences of alligator gar DNA and DNA of the spotted gar (from the same genus) are highly homologous (1-2% of nucleotide substitutions). The degrees of homology between repeated and unique sequences of alligator gar DNA and DNAs of the representatives of Acipenseriformes (the same super-order Ganoidomorpha), Latimeria chalumnae (another subclass, Sarcopterygii) and a shark (another class, Chondrichthyes) are of the same order, and the levels of divergency of their DNAs sequences are similar. These results demonstrate, that the joining of Lepisosteiformes and Acipenseriformes in one and the same group of Ganoidomorpha is artificial, and that the superclass of fishes, Pisces, includes more taxons of the class rank then it has been taken in theory.