Muller “Elements” in Drosophila: How the Search for the Genetic Basis for Speciation Led to the Birth of Comparative Genomics

The development of genetic maps multiple species of Drosophila to understand the basis for species formation became problematic because visible mutations were not easily compared among species and species-specific linkage groups lacked a standard nomenclature... The concept of synteny, or conservation of genes on the same chromosome, traces its origins to the early days of Drosophila genetics. This discovery emerged from comparisons of linkage maps from different species of Drosophila with the goal of understanding the process of speciation. H. J. Muller published a landmark article entitled Bearings of the “Drosophila” work on systematics, where he synthesized genetic and physical map data and proposed a model of speciation and chromosomal gene content conservation. These models have withstood the test of time with the advent of molecular genetic analysis from protein to genome level variation. Muller’s ideas provide a framework to begin to answer questions about the evolutionary forces that shape the structure of the genome.