The MRC Laboratory for Molecular Biology in Cambridge, the Medical Research Council Mammalian Genetics Unit in Oxfordshire, and some of their associates based in New York University have discovered that an "after-hours gene" may explain the nocturnal predisposition of some people. The said gene is currently being referred to as "after hours" or Afh. It is a variant of another gene called Fbxl3 which to date has not been linked to any body clock functions in the human body.

Their tests, which involved monitoring the exercise routine of mice on a wheel, have shown that those which possessed the after hours version of the Fbxl3 gene were running on a 27 hour body clock instead of the normal 24.

"The internal body clocks of mice with the after hours gene run on a longer cycle than mice that have a normal copy of the gene, who like most of us live on a 24 hour schedule." said Patrick Nolan of the MRC Mammalian Genetics Unit. He then gave a brief, if rather complicated explanation on this phenomenon saying "We found that mice that carried the after hours gene also had a delayed Cry protein (which is one of the key proteins that determine our body clock) breakdown rate, leading to a slowdown in the molecular feedback loops and a lengthening of the body clock cycle."

So nocturnal people unite, we finally may have the answer to why our bodies prefer night to day. Hopefully, further research will be done on this to confirm whether or not their findings really hold true.