The discovery presented in the article explains how a species can make what they call macroevolutionary changes (read: big changes) in the design of their bodies. The example they give is a bug with lots of legs changing into a bug with only a few legs by changing only one part of its genes.
"this could be accomplished with relatively simple mutations in a class of regulatory genes, known as Hox, that act as master switches by turning on and off other genes during embryonic development"
What I don't get is: if macroevolutionary changes occur by the Hox turning off existing genes and then turning on other existing genes, then that means that the genes that produced the new feature, the gene that was turned on, had to allready be there from the beginning.
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The discovery presented in the article explains how a species can make what they call macroevolutionary changes (read: big changes) in the design of their bodies. The example they give is a bug with lots of legs changing into a bug with only a few legs by changing only one part of its genes. "this could be accomplished with relatively simple mutations in a class of regulatory genes, known as Hox, that act as master switches by turning on and off other genes during embryonic development" What I don't get is: if macroevolutionary changes occur by the Hox turning off existing genes and then turning on other existing genes, then that means that the genes that produced the new feature, the gene that was turned on, had to allready be there from the beginning.