In living organisms, there have also been a lot of Traditionally held view of the flow of information Information to be from DNA to RNA to protein.

Structure of DNA and determined the flow of This particular gene is associated with predisposition to obesity, so by giving the mothers BPA, they altered the phenotype of the offspring without actually altering the DNA sequence.Īnother video in which I talk about the centralĭogma of molecular biology, and this being the work ofįrancis Crick and James Watson, who delineated the They found that intake of BPA during pregnancy can cause demethylation of the Agouti gene in the offspring, thus causing the gene to be expressed. The example given in my class was an experiment with BPA and the Agouti gene. Certain environmental factors can cause changes in the methylation pattern and cause some genes to be expressed or repressed. When DNA replicates, it keeps one of its parent strands, and an enzyme called DNA methyltransferase is responsible for transferring a methyl group to the daughter strand's cytosine where the parent strand has a cytosine.Īnyway, these (-CH3) groups prevent the DNA in that area from being transcripted by physically blocking protein binding in that area. Since DNA is double stranded, if there is CG next to each other on one strand, there will be CG on the complementary strand, and both of those cytosines are methylated in order to preserve the methylation sequence during replication. Some of those cytosine base pairs are methylated, meaning they have a (-CH3) group attached to them. We just talked about this in my biology class, so I am by no means an expert, but the general idea is this:ĭNA has 'CG' islands, which are cytosines next to guanines in the DNA sequence.

Khan academy molecular biology