DNA methylation and histone modification (Edexcel Int. A-level biology)

This lesson describes how epigenetic modifications like DNA methylation and histone modification can alter the activation of certain genes. The PowerPoint and accompanying resources have been planned to cover points 3.20 ii & iii of the Edexcel Internationational A-level biology specification, and also highlights that these modifications can be passed on following cell division.

The lesson begins by introducing the meaning of the prefix epi as on or above so students understand that epigenetics refers to changes in gene function due to factors beyond the genetic code. Moving forwards, they will learn that DNA methylation involves the attachment of a methyl group to cytosine and will come to understand how this inhibits transcription. They are challenged to recognise the pathogenesis of atherosclerosis through a variety of tasks before reading through a source detailing the results of a study between this cardiovascular condition and DNA methylation.

The remainder of the lesson considers how the acetylation of histone proteins affects the expression of genes.

Understanding and prior knowledge checks are embedded throughout the lesson (along with the answers) to allow the students to assess their progress on this topic and to encourage them to make links to the content of topics 1 - 2.