Genetic Facts: Black Grouses Don't Dance About Their Appearance!

Genetic Facts: Black Grouses Don't Dance About Their Appearance!

On August 11, 2025, a research team led by biologist Rebecca Chen from the Bielefeld University significant results on genetic variation and reproductive success of male black grouse. The study entitled “Predicted deleterious mutations reveal the genomic mechanisms underlying fitness variation in a lekking bird” was published in the renowned journal *Nature Ecology & Evolution*. The main thesis of the study is that it is less the externally visible characteristics of the males, but rather their behavior that has a decisive influence on mating success.

This finding revolutionizes previous assumptions about black grouse reproduction. Males carrying many harmful genetic mutations are less likely to be found at courtship sites (leks) and therefore miss out on significant reproductive opportunities. The study analyzed the complete genomes of 190 males, incorporating behavioral and reproductive observations over long periods of time. What is particularly striking is that both homozygous and heterozygous mutations have negative effects on reproductive success, which calls into question the previously prevailing view of genetic stress.

Effects of genetic changes

Research shows that mutations in regulatory DNA sections, especially in promoters, have a particularly serious impact. These impairments in the regulatory regions hinder the males' ability to adapt, particularly their courtship behavior. Females primarily observe this behavior when choosing a mate and not necessarily the physical characteristics of males.

The work is part of the Joint Institute for Individualization in a Changing Environment (JICE), which is located at the universities of Bielefeld and Münster. JICE aims to understand the individual differences of animals and humans in the context of environmental change. This study also links genetic data to behavioral and environmental factors to explain reproductive success in the wild.

Genetic diversity and reproductive success

However, the importance of genetic diversity extends beyond black grouse. Examined in a comprehensive context artenmortal.de the challenges associated with loss of genetic diversity. Long-term studies show that genetic diversity is crucial for a species' survival and its ability to adapt to environmental changes. A worrying finding is that two-thirds (66.6%) of the populations studied are losing genetic diversity, regardless of their threat status.

Birds and mammals are particularly affected, while some insect and fish species show stable genetic diversity. Loss of this diversity can be caused by a variety of factors, including habitat loss, disease and excessive hunting. Historical examples such as the thylacine and the quagga illustrate the dangerous consequences of such loss.

Genetic contamination is not only a problem for animals, but also for humans. An analysis of genetic data from the UK Biobank shows that harmful gene variants that can affect childlessness and cognitive ability are widespread. Carriers of a harmful gene often experience milder symptoms, challenging classifications of genetic diseases and highlighting the need for further research.

In summary, genetic diversity is of central importance both in black grouse and in broader biological contexts. The ongoing studies highlight the urgency to further investigate genetic factors in reproduction and health to ensure the survival and adaptability of species in a rapidly changing world.