Species as apparently different as flies, worms and humans have something in common within their cells at the molecular level, researchers say, and it's down to genomes.

An international consortium of researchers, looking at the ways genomes accumulate changes and mutations throughout evolution, say they've identified groups of genes that work together without regard to the organism in which they are contained, and therefore are likely essential for the entire animal kingdom, whether you're looking at worms, flies -- or humans.

These key genomic processes in common across species reflect a shared ancestry, they say, and also reveal clues to biological processes such as embryonic development and gene regulation that can help in understanding human biology and disease.

"One way to describe and understand the human genome is through comparative genomics and studying model organisms," says Mark Gerstein of Yale University, lead author of a paper appearing in the journal Nature.

"The special thing about the worm and fly is that they are very distant from humans evolutionarily, so finding something conserved across all three -- human, fly and worm -- tells us it is a very ancient, fundamental process," he says.

Gerstein's paper is one of three appearing in the Aug. 28 issue of Nature from the multi-institution research effort known as modENCODE, for Model Organism ENCylopedia Of DNA Elements.

The aim of modENCODE, established in 2007, is to generate a complete catalog of functional elements in the genomes of fruit flies and roundworms for use as model organisms by researchers studying the human genome.

Although those species seem too dissimilar from humans to serve as a research model, more than half the genes linked to human cancers and genetic diseases exist in the fly's genome, and have been found to cause comparable problems in the flies when they are mutated.

Genes can be damaged or mutated by radiation, chemical exposure or errors in DNA replication, the researchers said, and the subsequent results are often similar whether the gene is in humans, flies or worms.

The genes that apparently work together similarly in the three species are all related to development, supporting the hypothesis that all animals pass through a stage during embryonic development in which the expression of the genes common to all animals is most often seen.

"These findings give us a map of highly important regions of the genome that will guide the scientific community in future research projects related to cell biology and, in extension, to disease", says researcher Sarah Djebali at the Center for Genomic Regulation in Spain.