DNA Supergenes That Speed Up Evolution Have Been Found in Fish — and They Change What We Know About Species Formation

Scientists found DNA supergenes in cichlid fish that explain rapid species formation. Here is how this discovery changes evolutionary biology and what it means for human genetics.

Lake Malawi contains approximately 800 species of cichlid fish — a staggering diversity that evolved within the last 100,000 years from a common ancestor. For evolutionary biologists, this represents the fastest documented case of species diversification in vertebrate evolution, producing more distinct species than the entire bird fauna of Europe in a fraction of the time. How this happened has been an open question. A new genetic analysis published in April 2026 offers an answer that changes the conventional picture of how new species form.

The discovery involves what researchers are calling 'supergenes' — clusters of genes physically linked within chromosomes that function as single inheritance units, passing from parent to offspring as a coordinated block rather than as individually shuffled components. In cichlid fish, these supergenes contain multiple genes governing simultaneously the colouration patterns, mating behaviour preferences, and territorial strategies that distinguish species from each other.

The conventional picture of speciation involves gradual accumulation of many small genetic differences across many genes. The supergene mechanism suggests a different pathway: a single inheritance event can simultaneously transmit the coordinated package of traits that together constitute a distinct reproductive strategy. This 'all or nothing' inheritance pattern means that a new combination of mate-preference and display traits that is favoured by natural selection can spread through a population much faster than if each gene in the package had to become fixed independently.

The human genetics implication is specific and interesting. Supergene-like structures have been documented in human chromosomes governing trait combinations including height-and-obesity-risk packages, immune response profiles, and — most intriguingly — the specific chromosome inversions associated with differences in behaviour and neurological development. Whether these human supergene-like structures operate through similar evolutionary mechanisms to the cichlid case is an active research question that the new paper has directly stimulated.