A BURMESE python that has just eaten a goat may look like it鈥檚 resting, but on the inside it鈥檚 frantic. The python鈥檚 digestion switches on an unusually large number of genes.
Pythons eat large meals very infrequently. To conserve energy between meals, they mothball their innards, substantially shrinking most of their internal organs. Then, after a meal, their intestines more than double in mass, and the heart and kidneys increase by half.
This involves a huge amount of genetic turmoil. To find out just how much, and colleagues at the University of Colorado at Denver measured gene activity in the organs of Burmese pythons, Python molurus bivittatus, before and immediately after meals. About 1800 dormant genes switched on within 24 hours of a meal, they reported last week at . Similar activation also occurs in the liver, kidney and intestines, they say.
Advertisement
This is a staggering change: previously only a few dozen and up to a few hundred genes had been seen to change to cope with new conditions. Even the transition from an unfertilised egg to a 4-celled embryo 鈥� one of the biggest changes in an organism鈥檚 life 鈥� involves .