Transposable Element Expression Profiles in Premalignant Pigment Cell Lesions and Melanoma of Xiphophorus.

Transposable elements (TEs) are characterized by their ability to change their genomic position. Through insertion or recombination leading to deletions and other chromosomal aberrations, they can cause genetic instability. The extent to which they thereby exert regulatory influence on cellular functions is unclear. To better characterize TEs in processes such as carcinogenesis, we used the well-established Xiphophorus melanoma model. By transcriptome sequencing, we show that an increasing total number in transposons correlates with progression of malignancy in melanoma samples from Xiphophorus interspecific hybrids. Further, by comparing the presence of TEs in the parental genomes of Xiphophorus maculatus and Xiphophorus hellerii , we could show that even in closely related species, genomic location and spectrum of TEs are considerably different.