Variation in Melanin Content of Lizard Livers: Hybrids Turning to the Dark Side.

AbstractPigments such as melanin are most often associated with the surface of an organism, providing functions such as coloration and protection from UV radiation. However, the internal organs of some species also contain melanin. Internal melanin may also perform protective functions when cellular stress is experienced.

Functional Divergence of Mitochondria and Coevolution of Genomes: Cool Mitochondria in Hot Lizards.

Mitochondria play a key role in the ecology and evolution of species through their influence on aerobic metabolism. Mitochondrial DNA (mtDNA) and nuclear genomes must interact for optimal functioning of oxidative phosphorylation to produce ATP, and breakdown of coadaptation components from each may have important evolutionary consequences for hybridization. Introgression of mitochondria in natural populations through hybridization with unidirectional backcrossing allows the testing of coadaptation of mitochondria to different nuclear backgrounds.

Introgression of mtDNA in Urosaurus lizards: historical and ecological processes.

Introgression of mtDNA appears common in animals, but the implications of acquiring a novel mitochondrial genome are not well known. This study investigates mito-genome introgression between the lizard species Urosaurus graciosus, a thermal specialist, and U. ornatus, a species that occupies a wider range of thermal environments.

Hormones, performance and fitness: Natural history and endocrine experiments on a lizard (Sceloporus undulatus).

We used the "morphology-performance-fitness" paradigm (Arnold, 1983) as our framework to investigate endocrine control of performance and fitness in Sceloporus undulatus (Eastern Fence Lizard). Focusing on males, we used the "natural experiments" of seasonal, sexual, and developmental variation in growth and in exercise endurance to identify testosterone and corticosterone as potential modulators of performance and related traits of interest. We followed with experimental manipulations of testosterone to investigate functional relationships, both in the laboratory and in the field.

Isolation and characterization of microsatellite markers in tree lizards (Urosaurus ornatus).

Tree lizards (Urosaurus ornatus) are a highly accessible species useful in testing theories of life-history evolution and behavioural ecology. A polymerase chain reaction-based method was used to isolate nine polymorphic tetranucleotide microsatellite loci from the genome of these lizards. The isolated loci displayed 5 to 9 alleles in the populations screened.