Genetic Erosion

Genetic erosion

Genetic erosion refers to the loss of genetic diversity due to either extinction or loss of allele combination

(D. Upadhyaya, 2016. ). According to the UN, 75% of agricultural diversity has been lost over the last century(FAOUN, 2009.). Additionally, due to human intervention, one million species face extinction today (Reuters, n.d. ). This presents significant ecological and social risks which will be explained as follows.

Consequences

The consequences of genetic erosion are largely due to its impact on biodiversity. Genetic erosion decreases evolutionary potential, reducing population resilience and thereby increasing extinction risk (R.K., 2013. ). Due to the reduction of genes in the gene pool, adaptive gene variation decreases(R.K., 2013. ). Adaptive gene variation refers to a species changing its genetic composition in order to adapt to a habitat (Lai, 2012. ). In this manner, genetic erosion prevents necessary evolution, decreasing population survival by increasing susceptibility to disease and environmental stress (Lai, 2012. ). An example was observed in the wild butterfly population, where heterozygosity (a measure of genetic diversity) was relatively lower in threatened populations at approximately 80% of the time, and was on average 35% lower in threatened species compared to non-threatened ones. (Bradshaw, nd. ).

As such, genetic erosion reduces biodiversity, harming the status of agricultural, land and marine populations. The negative social impacts of genetic erosion lie in the importance of genetic diversity.  According to the American Museum of Natural History, “We value biodiversity both for what it provides to humans and the value it has in its own right.” (MNMH, nd. ) Humans obtain essential resources from biodiversity, with over 80% of human medicine derived this way (Brown, 2022. ). Examples of medicine obtained from biodiversity include aspirin, morphine and chemotherapy among many other life-saving treatments (Pavid, nd. ). Additionally, biodiversity provides clean air, water, and food security, and therefore is the foundation of human lifestyle. In this manner, human survival is impossible without genetic diversity. 

Causes

So, what causes genetic erosion? Why have rates of genetic erosion risen so rapidly over the last century?

Modern Agricultural Practice

A major cause of genetic erosion is modern agricultural practice. In order to adhere to the current market, farmers employ variety replacement with replacement of landraces, creating uniformity in Agro-Ecosystems ((Khouri, 2021. )). This is due to the profit incentive of modern high-yielding crops. Due to the replacement of old crops/genomes with new, high-yielding modern species and crops, native crop growth is reduced (Khouri, 2021. ). As such, native species face genetic erosion due to this, leading to extinction.

Environmental Degradation

Another human-related reason for genetic erosion is environmental degradation due to  industrialization, urbanisation, overpopulation and deforestation (Maurya, nd. ). Environmental degradation causes habitat loss, reduction in species survival rate and increase in extinction rates, thereby causing genetic erosion. Additionally, species which are genetically eroded but not extinct have limited adaptive gene variation and therefore are even less able to adapt to environmental degradation, leading to further erosion and extinction (Lai, 2012. ). 

An example of environmental degradation causing extinction is degradation of coral reefs, where due to overfishing, pollution, and climate change the world lost about 14% of its coral between 2009 and 2018 (UN, 2021.). As a result, 59% of shark and ray species which depend on coral-reef are threatened with extinction (Sherman, nd.).

Conclusion

As such, the threat of genetic erosion is a major global issue which requires immediate intervention. Unfortunately, the problem of genetic erosion is much larger than any individual and requires either collective or government action. Some ways to reduce genetic erosion are the removal of harmful stressors and pests, incentivising the growth of native species as well as the reintroduction of species into their original habitat. As an individual, however, you can raise awareness and improve your knowledge about pollution, waste management and climate change to reduce your own environmental degradation.

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