This project will address the influence of genotype on vertebrate mortality. In particular, two types of genes will be considered: microsatellites and major histocompatibility complex (MHC) genes. Microsatellites have no known function and may be "junk" DNA, but occur thousands of times in vertebrate genomes. Conversely, MHC genes are usually consolidated in a particular region of the genome and are directly involved in the immune response. Tiger salamanders will be studied (bred, genotyped, and monitored) because 1) they serve as models for immunologists as well as for neurologists interested in olfaction; 2) they are long-lived creatures that have large families which provide the sample sizes needed to study mortality/survivorship; and 3) salamanders are of conservation interest, and some scientists think the global decline in amphibian populations is due to MHC-related pathogens. The results of this project could influence our thoughts on embryo mortality in other vertebrates, including humans. In viviparous (live-bearing) species like mammals, spontaneous abortion attributable to maternal/fetal incompatibility is difficult to study. However, such trends may be easier to document in salamanders that have internal fertilization but external development. Furthermore, this study will determine if MHC-based mate choice (as found in humans, rodents, and fishes) also exists in amphibians.
