Genes and Genetics 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.

Every cell of every individual of every species contains genes. No two individuals have exactly the same genes – that is, unless they are clones. The discovery of genes, what they look like and how they are passed from parent to child, led to a revolution in science in the nineteenth and twentieth centuries.

In one experiment, Gregor Mendel selected a tall plant, then crossed (or bred) it with a short plant. He observed how high the plant offspring grew and then how high the next generation of offspring grew. Looking at the pattern of tall-to-short plants, he was able to describe the basic laws of genetics. These laws, roughly summarised, state that when two parents reproduce each will pass on only half of their genetic material to their offspring. Each offspring will have exactly the same number of genes from their mother, and their father. These genes are passed on quite randomly, so all offspring inherit something different and no two siblings are quite the same, as can be seen in the figure on the opposite page. 

There are exceptions, however. Identical twins are nearly genetically identical, thanks to a rare event in nature where one fertilised egg divides and develops into two offspring. In certain plant families, clones are actually the norm. For instance, when a new bamboo or banana plant shoots up from the side of a parent plant, it is a clone.

opposite page: Flower of pea plant.
© Giulia Tiddens