Gene Duplications are a common starting point for the evolution of new genetic information. When gene duplications occur, they dramatically lengthen the genetic code of an individual. As point mutations add up in the duplicated region across generations, entirely new genes with new functions can evolve.
Scientists have directly and indirectly observed gene duplication events in the lab and in wild populations of plants, animals and microbes, many times over. Because of this, they can use known signatures of gene duplication events to understand how a large variety of genes evolved in plants and animals alive today.
In this video we see three examples of gene duplications resulting in new traits for the creatures who inherit them: the evolution of a venom gene in snakes, the evolution of leaf digestion genes in monkeys, and the evolution of burrowing legs in hunting dogs.
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Jianzhi "George" Zhang, PhD
Joanna Masel, PhD
Kini R Manjunatha, PhD
Nicholas Casewell, PhD
This video was sponsored in part by Gene-Tools LLC, a company producing molecules used to study cancer and gene function. If your lab studies genetics, cancer, or developmental biology, make sure to check them out at http://www.gene-tools.com/
How do new genes evolve?
Read about the many different ways in which entirely new genes come into existence: http://www.nature.com/scitable/topicpage/origins-of-new-genes-and-pseudogenes-835
Observed gene duplications In Bacteria
Here, gene duplication was directly observed from generation to generation. After duplication, a new function was seen to evolve.
Observed or inferred gene duplications In mice
Here, genetically identical mice were allowed to breed for several generations and then gene number variations were compared in the final populations.
Here, gene number variations were compared among populations of wild mice.
Factor X Snake venom evolution
Factor X is what it’s called in the blood.
Trocarin D is what it’s called in the venom gland.
Snake venom is modified saliva
The venom gland is derived from what are called “Dental Glands” which are found in reptiles and produce oral secretions like our saliva glands. In particular, the venom gland appears to be homologous to the Duvernoy's gland in non-venomous snakes. Little research has been done on the function of Duvernoy’s glands in non-venomous snakes but in most species, its secretions appear to be used as lubrication to aid in swallowing. Enzymes are also produced that may aid in killing, paralyzing, and digesting prey but these functions appear to be limited in their power and are only found in certain species.
How do blood clots form?
Read an overview of how the blood clotting cascade functions and may have evolved:
Watch a cool 3D animation showing how Factor X interacts with other molecules and structures in the blood to form clots!