Divergent patterns of selection on the DAB and DXB MHC class II loci in Xiphophorus fishes.

Two MHC class II loci, DAB (a classical class II locus) and DXB (putatively a non-classical class II locus), were sequenced in samples of individuals from two populations of swordtail fish, Xiphophorus multilineatus and X. pygmaeus. The DAB locus showed higher levels of genetic variation in the B1-encoding region, (putative binding region) than the DXB locus.

Characterization of XM, a novel Xiphophorus melanoma-derived cell line.

Xiphophorus species, inbred strains, and interspecies hybrids have been used extensively to understand the genesis of melanoma and other types of malignancies. Despite sophisticated studies on the genetics of this model, biological studies have been limited by the availability of characterized cell lines. The authors have established a melanoma-derived cell line, XM, from the most commonly used interspecies hybrid model for studies of the genetics and cell biology of melanoma in Xiphophorus.

Conservation of synteny between guppy and Xiphophorus genomes.

The guppy and fish in the genus Xiphophorus have both been important model systems for the study of natural and sexual selection for over 50 years. Whereas the guppy is unique in the degree to which the environmental variables shaping phenotypic variation are known, Xiphophorus has the advantage that genomic resources have been developed due to the utility of this taxon for the study of melanoma. If linkage maps for the guppy and Xiphophorus are similar, genomic resources developed in Xiphophorus will be useful in the guppy.

The genus Xiphophorus in Mexico and central america.

The genus Xiphophorus is found from northeastern Mexico (Coahuila) for about 2200 Km as far as Honduras. There are 26 species, of which 21 occupy headwaters on the eastern slope of the Sierra Madre Oriental and continuing Cordillera to the southeast. Virtually all the species in the headwaters occupy limited ranges, often in rivers traversing karst country that are separated from lowland streams by underground passages.

Allele-specific marker generation and linkage mapping on the Xiphophorus sex chromosomes.

There is great interest in the sex chromosomes of Xiphophorus fishes because both WY/YY and XX/XY sex-determining mechanisms function in these species, with at least one taxon possessing all three types of sex chromosomes, and because in certain interspecific hybrids melanoma arises as a consequence of inheritance of the sex-linked macromelanophore determining locus (MDL). Representational difference analysis (RDA) has been used to clone two sequences from the sex-determining region of X. maculatus, including a cholinergic receptor, nicotinic, delta polypeptide (CHRND) orthologue.