4 You are a forensic pathologist working in Northern Russia

4) You are a forensic pathologist working in Northern Russia. An early hominid has been preserved and found in the permafrost. It is believed that a gene related to causing obesity has been replicated and mutated through evolution. The exact location of the sequence has not yet been identified in early hominids. However there are 5 homologues in humans, two of which are known to be expressed. How could you locate the gene in the early hominid and verify whether both genes (hominid and human) are expressed and lead to obesity.

Solution

MC4R codes for a protein called melanocortin 4 receptor, which is mainly found in the hypothalamus of the brain, an area responsible for controlling appetite and satiety. Mutations in MC4R are the most common genetic cause of obesity. SNP (single nucleotide polymorphisms) of MC4R gene is associated with overweight and obesity. One SNP ( rs17782313) located downstream of MC4R is confirmed to be associated with overweight and obesity.