Thursday, 27 January 2011
Every person inherits half of their genetic information from their mother and half from their father, which occurs at fertilisation when the sperm and egg meet. The chromosomes inherited from each parent are the same and form pairs in mitosis. Normally both the maternal and paternal copies of each gene are expressed, and when one or both is mutated then this can sometimes lead to disease. However, there is a special situation for a few genes where only one of the parental genes is allowed to be expressed and the other copy is ‘turned off’. This was discovered when patients affected by two very different diseases were discovered to have mutations in the same gene, and which disease they developed was depended on the parent that the mutated gene was inherited from. Further discoveries have been made in this direction by the identification of a gene which is only expressed in some tissues of the body when inherited from one parent and expressed in other tissues when inherited from the other parent, but never are both copes expressed in the same tissues. The outline of the research is posted on the New Scientist website with the article ‘Ma's gene does different things to pa's copy’ 1, this is a nice article discussing the complex genetic mechanisms we are only just beginning to understand, and is likely to change our understanding of genetics and inherited risk factors for disease.
E Markham (2011). Interesting Imprinting Blogspot