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Submitted by kheredia on Thu, 10/31/2019 - 10:57

Gene duplication is a mechanism where genetic material is essentially generated and copied in a region of DNA. A regulatory mutation is a mutation that affects the spatial or temporal regulation of the gene without causing an entire loss of the gene product. Lastly, coding sequence mutations are changes in the coding sequence that can have different outcomes in expressivity like nonsense or missense mutations.

These three factors combined aided the use of a snake's venom to evolve into what it is today: from defensin genes that are used for different basic tasks like fighting infections in the pancreas, to today’s cromatine genes that encode the venom molecules and are used for attacking and destroying muscles. These changes did not alter the universal product of the gene, but in turn changed the way the genes were communicating. By sequencing genes from different snakes and mapping them out in an evolutionary tree, scientist Fry, colleagues compared the relationship of defensive and cromatine genes and found out that they are closely related. In newer generations that inherited the defensive gene, gene duplication took place for this change to occur.

There may have been an accidental duplication of a gene in which in turn would spark a new gene recruitment. Regulatory gene mutations would occur because gene recruitment now took place, helping change the gene’s functions through mutations: one of these copies would now be able to produce proteins in a venom gland. At the DNA level, a type of mutation could have occurred at the coding sequence by changing the amino acids, which, for this example, could have changed the expression of a gene from being a defensin gene to cromatine even by one difference in sequencing. Having these factors repeatedly happen over and over again in snakes eventually gave rise to a new family of venom producing genes.