Upgrading Molecular Cytogenetics to Study Reproduction and Reproductive Isolation in Mammals, Birds, and Dinosaurs

The past 10–15 years have seen a revolution in the field of genomics, first with the human genome project, followed by those of key model and agricultural species (chicken, pig, cattle, sheep) and, most recently, ∼ 60 de novo avian genome assemblies. The ultimate aim of a genome assembly is to create a contiguous unbroken length of sequence from p- to q-terminus to facilitate studies of gene mapping, trait linkage, phylogenomics, and gross genomic organization/change. Chromosome rearrangements are biologically relevant both in the context of reduction in reproductive capability of individual animals and in the establishment in reproductive isolation as species evolve and diverge. Moreover, a karyotype effectively represents a low-resolution map of the genome of any species. In investigating all these aspects, FISH remains the tool of choice, and this study describes a step change in its use.