New research (published May 12, 2015 in Nature Communications – paywall) suggests that gene expression “varies not only during the day but also throughout the year.”
The research raises new questions. For example, is there a “Cubs gene,” and does it have a pattern of seasonal expression that may help to explain Cub fans who are euphoric in the spring and summer, but morose in the fall. :)
The science story also is told in The Scientist.