Effect of genetic variants on phenotype
The structure of Deoxyribonucleic acid. The material inside the nucleus of cells, carrying the genetic information of a living being. is important in making specific The production of proteins from amino acids, which happens in the ribosomes of the cell. needed in biological processes.
Not all parts of the DNA code for proteins. In fact, it is believed that a human is made from only about 20,000 The basic unit of genetic material inherited from our parents. A gene is a section of DNA which controls part of a cell's chemistry - particularly protein production.. This means that there are large parts of our DNA which don't make proteins. We call these non-coding regions.
However, there are sections of non-coding DNA which can switch genes on and off. Not all the genes you need to survive are needed throughout your life. Some regions of these non-coding DNA are not as good as binding to RNA polymerase. This means the enzyme is less likely to bind and so less protein is produced. If less protein is produce this can affect the The visible characteristics of an organism which occur as a result of its genes. of the organism.
The diagram below shows DNA with certain genes switched on and others switched off:
Red boxes - genes switched on
White boxes - genes switched off
This diagram shows all of the genes are switched off:
In different cells around the body, certain genes will be switched on and others will be switched off. This will vary depending on which cells you examine.