Horizontal Gene Transfer in Animals
(a) Red aphids get their color from red carotenoid pigment. Genes necessary to make this pigment are present in certain fungi, and scientists speculate that aphids acquired these genes through HGT after consuming fungi for food. If genes for making carotenoids are inactivated by mutation, the aphids revert back to (b) their green color. Red coloration makes the aphids a lot more conspicuous to predators, but evidence suggests that red aphids are more resistant to insecticides than green ones. Thus, red aphids may be more fit to survive in some environments than green ones.
Source
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"OpenStax College, Perspectives on the Phylogenetic Tree. December 15, 2013."
http://cnx.org/content/m44593/1.5/
OpenStax CNX
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