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Diverse animals use Earth's magnetic field to guide their movements, but the neural and molecular mechanisms underlying the magnetic sense remain enigmatic. One hypothesis is that particles of the mineral magnetite (Fe 3 O 4 ) provide the basis of magnetoreception. Here we examined gene expression in the central nervous system of a magnetically sensitive invertebrate, the Caribbean spiny lobster (Panulirus argus), after applying a magnetic pulse known to alter magnetic orientation behavior. Numerous genes were differentially expressed in response to the pulse, including 647 in the brain, 1256 in the subesophageal ganglion, and 712 in the thoracic ganglia. Many such genes encode proteins linked to iron regulation, oxidative stress, and immune response, consistent with possible impacts of a magnetic pulse on magnetite-based magnetoreceptors. Additionally, however, altered expression also occurred for numerous genes with no apparent link to magnetoreception, including genes encoding proteins linked to photoreception, carbohydrate and hormone metabolism, and other physiological processes. Overall, the results are consistent with the magnetite hypothesis of magnetoreception, yet also reveal that in spiny lobsters, a strong pulse altered expression of > 10% of all expressed genes, including many seemingly unrelated to sensory processes. Thus, caution is required when interpreting the effects of magnetic pulses on animal behavior.

Across diverse taxa, an increasing number of photoreceptive systems are being discovered in tissues outside of the eye, such as in the skin. Dermal photoreception is believed to serve a variety of functions, including rapid color change via specialized cells called chromatophores. In vitro studies of this system among color-changing fish have suggested the use of a phototransduction signaling cascade that fundamentally differs from that of the retina. Thus, the goal of this study was to identify phototransduction genes and compare their expression in the retina and skin of a color-changing fish, the hogfish Lachnolaimus maximus. De novo transcriptomics revealed the expression of genes that may underlie distinct, yet complete phototransduction cascades in L. maximus retina and skin. In contrast to the five visual opsin genes and cGMP-dependent phototransduction components expressed in the retina of L. maximus, only a single short-wavelength sensitive opsin (SWS1) and putative cAMP-dependent phototransduction components were expressed in the skin. These data suggest a separate evolutionary history of phototransduction in the retina and skin of certain vertebrates and, for the first time, indicate an expression repertoire of genes that underlie a non-retinal phototransduction pathway in the skin of a color-changing fish.

The technique to produce hybrid Tulu or Nar camels from crosses between dromedary and Bactrian camels is common throughout Middle Eastern and Central Asian countries. Formerly, these hybrids were highly valued as strong and persistent pack animals but today are bred to improve milk or wool quality in the respective species and for camel wrestling. We developed a diagnostic single nucleotide polymorphism (SNP) panel to identify cryptic ancestry in F 1 hybrids and their backcrosses by selecting loci from whole genome data, which were fixed for different alleles in either dromedary or domestic and wild Bactrian camel. With this SNP panel we are able to identify the hybridization patterns in camels with uncertain origins, support hybrid breeding management and to detect potential rare dromedary introgression in the last wild Bactrian camels in Mongolia and China.