Genetic Diversity

Source: Food and Agriculture Organization of the United Nations, 2013, Cary Fowler, Charlotte Lusty and Maria Vinje Dodson, and Global Crop Diversity Trust, "The Youth Guide to Biodiversity" 1st Edition (Chapter 3) Youth and United Nations Global Alliance. Reproduced with permission.

Chapter 3. Verbatim.

Putting it simply, genes produce traits. A trait is a characteristic such as curly hair, freckles or blood type. Genes act singularly or in combination to produce traits, many of which are very obvious. Human eye colour, for instance, is determined by a combination of genes, giving colours of blue, green, brown, hazel, grey, chestnut and variations in between. This is genetic diversity.

When you look at the eyes of the population of a town or country in Europe or North America, there may be great variation in eye colour. Elsewhere, for instance in parts of Africa and Asia, eye colour may not vary much at all.

The eye colour example shows diversity within a single species – the human species. But there’s also genetic diversity within a group of species – pigeons, for instance! If you travel to an island or a forest in the tropics, you will almost certainly find pigeons. You will recognise that they are pigeons, but they are not the same as the pigeons you know from back home. They are genetically quite different, although clearly related. There are many more diverse groups of species than pigeons, especially in the insect world! 

In a similar way, we can measure the total genetic diversity of an ecosystem. Some ecosystems are more diverse than others. A small area of forest on the Atlantic coast of Brazil contains more plant and animal species, and therefore more genetic diversity, than the entire USA .