THE GLUTAMATE-DEHYDROGENASE, E74 AND PUTATIVE ACTIN GENE LOCI IN THE DROSOPHILA-MONTIUM SUBGROUP - CHROMOSOMAL HOMOLOGIES AMONG THE MONTIUMSPECIES AND DROSOPHILA-MELANOGASTER

DNA-specific sequences from an enzyme-coding gene (glutamate dehydroge nase, gdh), a regulatory protein-coding gene (E74) and genes of the ac tin family were mapped by in situ hybridization on the polytene chromo somes of six species representative of the geographical distribution o f the Drosophila montium subgroup of the melanogaster species group. I n all species studied, one hybridization signal was detected for the g dh and E74 genes, and seven signals for the actin genes. The distribut ion of the actin-related loci in five montium species is similar to th at of the other Drosophila species studied so far, although they prese nt an extra signal. This distribution differs in the sixth montium spe cies studied, D. kikkawai. Taking into account the present results, as well as previous data obtained mainly by in situ hybridizations, homo logies among the polytene chromosomes of the montium subgroup species, as well as between these species and D. melanogaster, were also estab lished.