There are about 8.7 million species of living organisms on our planet, resulting from a long evolutionary process. Each of them carries a unique gene pool – a set of gene variations occurring within a single population. But environmental degradation leads to the depletion of the gene pool and the extinction of many species.

Causes of changes in the gene pool of the population

The genetic code is passed on from generation to generation. The more individuals have a certain allele – the form of the gene that determines the appearance of a characteristic trait in the population – the higher the probability that the gene pool will be preserved. That is, a large population size guarantees the transmission of gene diversity to future generations. This is important for successful disease resistance and adaptation to negative environmental factors. When the number of species decreases, the risk of unhealthy offspring in genetically related individuals increases.

An important factor influencing random changes in the gene pool is migration. When a population settles in new territories, individuals adapt to environmental conditions. For example, when moving to a habitat with a colder climate, natural gene selection will be aimed at increasing frost resistance. And if camouflage is necessary for survival, the coloration will begin to change little by little.

Also, the gene pool of populations is negatively affected by the disappearance of wild species and the emergence of many breeds with a similar gene set. Captive breeding often results in mutations that are passed on from generation to generation. In the wild, weak individuals die, while under the vigilant control of the breeder they may survive and be allowed to reproduce.

Another cause of changes in the gene pool is deforestation, construction of roads and dams, which cause the separation of wildlife habitats. A busy highway in the middle of a forest can be an insurmountable obstacle for many species. This leads to a decrease in genetic diversity and triggers the extinction process of populations.

Changing the gene pool is the greatest threat to all living things

Many people have heard of the butterfly effect. It means that all species are interconnected and any change in the gene pool affects the ecosystem as a whole. For example, herbivorous animals restrain the spread of fast-growing plants, maintaining the species diversity of flora, while predators control the number of their victims, clearing populations of weak and sick individuals.

Maria Orlova, candidate of biological sciences, notes that so-called “pests” play an important role in maintaining the balance of the ecosystem. Parasites can regulate reproductive function – in crustaceans. Or protect the territory from being colonized by other species that feed on the same food. For a long time, wildlife experts did not take this feature into account and did not understand why mortality and reproductive ability among animals relocated to a new place increased. It turned out that the immunity of local populations adapts to parasites and they are pathogenic to invasive species.

Active pest control usually does not lead to their complete elimination. But the set of genes left in living individuals is limited and altered by the chemicals used against them. According to a joint study by scientists from the University of Sydney and the University of Queensland, as well as from the Chinese Academy of Agricultural Sciences in Beijing, the overall insect population is declining at a catastrophic rate of 2.5% per year. That is, in 100 years, insects may disappear, leading to the death of many species of plants, reptiles, amphibians and birds. The surviving birds will start attacking each other, such cases have already happened in Australia.

The numbers of some populations are not a cause for concern, even in the face of an altered gene pool. But, as studies have shown, species that easily adapt to new conditions become the most dangerous vectors of disease and displace other representatives of fauna.

Humanity has not only an indirect impact on the gene pool, but also a direct one. Thus, breeding, which, at first glance, increases biodiversity, weakens the population. In the process of breeding new breeds, alleles found to be undesirable are removed from the gene pool. But in doing so, the animals often become more susceptible to disease and infection. Many of them cannot survive without humans. Once in the wild, they cross with wild animals and pass on genes responsible, for example, for their bright coloring, which can be seen by predators from a distance, or for their tendency to develop joint diseases. This upsets the balance and brings rare species closer to extinction.

Measures to preserve the gene pool of populations

1. Creation of the Red Book. Animals included in the Red Book are protected by the state and conservation organizations, including the World Wildlife Fund. Hunting them is a criminal offense. This stops the depletion of the gene pool and helps restore population numbers.

2. The cryopreservation method makes it possible to freeze biological material of endangered animal species. There are 22 such gene banks around the world, but so far cryopreservation has been slow. This is due to the difficulties in studying the reproduction process of populations and limited access to individuals listed in the Red List.

3. Conservation of species numbers. In recent decades, scientists have developed programs to increase the number of individuals of many endangered species. Not so long ago, such practices were viewed with skepticism. But it turned out that the captive-born cubs successfully adapted to the wild environment in which their parents lived. Many species have been saved from extinction in this way, including the giant panda, the bison and the Pyrenean lynx.

4. Care for nature – controlling deforestation, low-waste production, cleaning water from oil film, limiting hunting of wild animals. For the protection of endangered species nature reserves and wildlife sanctuaries were created, in Russia they occupy about 170 thousand km2.

5. Ecological corridors are created to restore the connection between the parts of the disturbed ecosystem. These are forest belts and river valleys. The length of ecological corridors reaches 3,000 km, and their width varies from 1 to 10 km. Their main functions are the exchange of genetic information between species, restoration of biodiversity and population size.