INTRODUCTION In 65 genotypes of Xiphophorus (nonhybnids and inter populational and interspecific F and backcnoss hybrids), the susceptibility to neuroblastoma following treatment with carcinogenic-mutagenic agents was tested. The fish were exposed to an aqueous solution of N-methyl-N-n itro sounea (MNU) or exposed to X-rays. Neunoblastoma was induced by MNU in 64 of about 3500 treated fish and ...

In Xiphophorus, the causative genetic information for melanoma formation has been assigned by classical genetics to chromosomal loci, which are located on the sex chromosomes. In our attempts to molecularly clone these melanoma-determining loci, named Tu, we have looked for restrictionfragment-length markers (RFLMs) linked to the Tu loci. These RFLMs should be useful in obtaining a physical map...

Introduction Fish models have become very popular during the past decade (see Fig. 1 for phylogenetic relationships). Recently established models for genomic studies (the Japanese and freshwater pufferfish, Fugu rubripes and Tetraodon nigroviridis, respectively) and for developmental biology (the zebrafish, Danio rerio) are now the focus of interest of many biologists, although ‘old’ models are...

Genetic mechanisms of sex determination are unexpectedly diverse and change rapidly during evolution. We review the role of genetic conflict as the driving force behind this diversity and turnover. Genetic conflict occurs when different components of a genetic system are subject to selection in opposite directions. Conflict may occur between genomes (including paternal-maternal and parentalzygo...