Mitochondrial Gene Markers for the Hybridizing Toads Bufo microscaphus and Bufo woodhousii in Arizona
Three restriction site markers from the mitochondrial genome are described for the toads Bufo microscaphus and B. woodhousii. Markers were resolved from DNA sequence data representing segments of cytochrome b (cytb) and 16S ribosomal genes. Two diagnostic restriction sites (BsmA I; SfaN I) characterize B. microscaphus for cytb, whereas a third restriction site (Tsp509 I) distinguishes B. woodhousii for 16S. Restriction digests of PCR-amplified cytb and 16S segments provide an economical, nondestructive assay with which to identify mtDNA haplotypes for these toads and their hybrids. The mtDNA markers complement diagnostic allozyme and call characters, offering an additional approach to examine hybridization between the two species in central Arizona.Abstract

Locations surveyed to establish diagnostic mitochondrial markers for the toads Bufo microscaphus and B. woodhousii. Bufo microscaphus locales are represented by open circles and those for B. woodhousii with closed circles; sample sizes are listed by each locale. The hybrid zone under investigation is delimited by a rectangle

Restriction site profiles for Bufo mitochondrial markers. From left to right, lanes 1 and 2 are BsmA I digests of cytb for microscaphus and woodhousii, respectively; lanes 2 and 3, SfaN I digests of cytb for microscaphus and woodhousii; lane 5, a 100 bp ladder; and lanes 6 and 7, Tsp509 I digests of 16S for microscaphus and woodhousii