Gene banks for animals and plants are vital for maintaining and preventing the loss of Genetic Diversity. This diversity is important for the survival wild animals and plants and also for the future of agriculture.
The following pages look in more detail at the role of Zoos and Seed banks in preventing genetic loss. (also see loss of biodiversity)
Some biological background:
- Natural selection cannot operate unless there is genetic variability within a population.
- A population with a small gene pool would be unlikely to survive long periods of time because it lacks the ability to make evolutionary adjustments as conditions change.
- Artificial selection (as seen in agriculture) cannot select for new varieties if the gene pool is too small.
- Genetic variability and indigenous populations are important because:
- They ensure the survival of species, especially those which are in small numbers and endangered.
- Ensures continued development of new varieties for agriculture.
- Increase yields of plants and disease resistance by crossing with wild types.
- Indigenous species represent a potential new crop: at present only 30 plants account for 95% of human nutrition.
- Genetic erosion (or loss of genetic variability) is now so rapid that within 50 years natural habitats will have little to offer to plant breeders searching for new variability.
- So far scientists have looked at only 10% of the Earths species but at extinction rates of 50 per day, time may well be limited.
- Causes of genetic erosion are:
- Advances in plant breeding: there are now fewer and fewer varieties of food crops due to the need for uniformity in agriculture (size, ripening times, yield etc). This has narrowed the genetic base.
Activity: How many different types of potato ( or another vegetable) can you find in your local supermarket? Ask your grandparents what varieties they had when they were your age? Are they the same as now? Where they the same? Where they as good?
- Framing trends: there has been a loss to the genetic pool when old pastures are ploughed up to reseed with modern ‘improved’ varieties. Examples can been seen on the Somerset Levels and the Romney marshes in Kent.
- Population increase: this has led to the loss of habitat and pollution.
- Loss of old/rare breeds: many of these are commercially unviable so only a few breed/varieties are used by agriculture. Around the UK are an increasing number of rare breeds centers e.g. Rare Breeds Center in Kent
The risks of Genetic uniformity : some examples