ABSTRACT
The complete DNA sequence of the mitochondrial genome of the bullsnake (Pituophis catenifer sayi) is presented and analyzed in this study. The genome is 17,193 bp in length, and contains 22 transfer RNA genes, 2 ribosomal RNA genes, 13 protein-coding genes and 2 control regions. The overall base composition of the H-strand is A (34.5%), T (26.2%), C (25.8%) and G (12.7%). The gene order and orientation of the mitogenome is consistent with other sequenced genomes from colubrid snakes. Phylogenetic analyses using the ML, NJ and MP methods for a set of colubrids, including every sequenced genus within the sub-family Colubrinae, produced identical trees. We show that Pituophis is most closely related to the American ratsnake genus Pantherophis.
ABSTRACT
RAPD markers were used to examine the degree of genetic variation within the putatively asexual basidiomycete fungus (Lepiotaceae: provisionally named Leucoagaricus gongylophorus) associated with the leaf-cutting ant species Atta cephalotes. We analyzed fungal isolates from ant nests in two geographically distant sites, two isolates from Panama and five isolates from Trinidad. Ten decamer primers were used to amplify total DNA from these seven fungal isolates, and RAPD banding patterns were compared. Genetic similarity among isolates was determined by pair-wise comparisons of the shared number of DNA bands on an agarose gel. There was considerable genetic variation among isolates of the symbiotic fungus even within sites. Pairs of fungal isolates from the two different sites shared an average of only 36% of the bands in their RAPD profiles, while pairs from the within sites shared an average of 72% of the bands. RAPD markers may be useful for further investigation of the genetic structure of the fungal symbiont within species of leaf-cutting ants.