Identification of newts (Triturus sp.) and their hybrids using molecular methods

Identification of hybrids is important for the study of introgression betwe en related species, but can be difficult when morphological differences bet ween parental species are small. In the case of the newts Triturus vulgaris and T. helveticus, males are readily identifiable during the breeding seas on when secondary sexual characters are highly developed, but female dimorp hism is always much less. Male hybrids with intermediate characters are the refore more likely to be detected than female ones. RAPD (random amplified polymorphic DNA) analysis of three putative newt hybrids and examples of th e two parent species T. vulgaris and T. helveticus confirmed hybrid status in all three cases. The maternal parents of each hybrid were identified by amplification of mitochondrial cytochrome b and ATPase genes, including par tial sequencing of the latter. One hybrid had a T. vulgaris mother while th e other two had T. helveticus mothers. The PCR-based methods therefore prov ided a quick and simple approach for identifying both hybrid status and par entage in crosses between these two urodele species. The RAPD technique sho uld also prove useful for the identification of larvae, which are morpholog ically indistinguishable in T. vulgaris and T. helveticus.