Changes

One strand of [[DNA]] contains many genes. DNA is made of four [[nucleotide]]s, [[guanine]], [[adenine]], [[thymine]] and [[cytosine]]. G always pairs with C, and A with T. Different combinations of GC and AT join together in different orders along the strands of DNA coiled up along our [[chromosome]]s to give our cells instructions for making the different kind of protein of which our bodies are made. These groups of instructions are called genes. Our bodies are made up of about 100 trillion cells, each of which is responsible for a specific function. The thousands of different proteins in the cells work together like a machine to make the [[cell]] function as it should. If the genes are normal, the body part will function well. If a change (mutation) has happened in a gene, the protein may be faulty, as for example in sickle cell anemia where the instructions for making [[blood]] cells are abnormal.

One strand of [[DNA]] contains many genes. DNA is made of four [[nucleotide]]s, [[guanine]], [[adenine]], [[thymine]] and [[cytosine]]. G always pairs with C, and A with T. Different combinations of GC and AT join together in different orders along the strands of DNA coiled up along our [[chromosome]]s to give our cells instructions for making the different kind of protein of which our bodies are made. These groups of instructions are called genes. Our bodies are made up of about 100 trillion cells, each of which is responsible for a specific function. The thousands of different proteins in the cells work together like a machine to make the [[cell]] function as it should. If the genes are normal, the body part will function well. If a change (mutation) has happened in a gene, the protein may be faulty, as for example in sickle cell anemia where the instructions for making [[blood]] cells are abnormal.

In 2005 it was shown that genes were not the only way that genetic information could be inherited. Scientists working at Purdue University discovered that Arabidopsis plants could remember what genes they had in the past, and correct mistakes in their current genes. This non-mendelian inheritance probably involves a RNA cache of past messenger RNA transcripts.

In 2005 it was shown that genes were not the only way that genetic information could be inherited. Scientists working at Purdue University discovered that Arabidopsis plants could remember what genes they had in the past, and correct mistakes in their current genes. This non-mendelian inheritance probably involves a RNA cache of past messenger RNA transcripts.<ref>[http://www.ncbi.nlm.nih.gov/pubmed/15785770?ordinalpos=15&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum 2005 study]</ref>

==Mutation==

==Mutation==