Physical map of the mitochondrial DNA from the phycomycete Allomyces macrogynus including the position of the ribosomal RNA genes and of an intervening sequence in the large rRNA gene

Abstract

The mitochondrial (mt) DNA of the aquatic phycomycete Allomyces macrogynus is a circular molecule with a size of 56.1 kbp. The cleavage sites for the restriction enzymes SalI and PvuI were mapped by comparing the partial denaturation patterns of isolated restriction fragments with the pattern of the intact circle.The genes coding for the small and large ribosomal RNA (rRNA) were located on the restriction map by heteroduplex and R-loop analysis. The gene coding for the large rRNA contains an intervening sequence, app. 0.7 kbp in size, near the 3'-end of the gene. The two rRNA genes are encoded on the same strand of the mtDNA and separated by a region of 17-18 kbp.This rRNA gene organization is similar to that found with members of the Ascomycetes.