• DOI:10.1126/science.1187113
• Corpus ID: 14785276

Lateral Transfer of Genes from Fungi Underlies Carotenoid Production in Aphids

@article{Moran2010LateralTO,
  title={Lateral Transfer of Genes from Fungi Underlies Carotenoid Production in Aphids},
  author={Nancy A. Moran and Tyler Jarvik},
  journal={Science},
  year={2010},
  volume={328},
  pages={624 - 627}
}

• N. Moran, T. Jarvik
• Published 30 April 2010
• Biology
• Science

Pink for Me, Green for You Aphids come in different colors, a critical issue when fate is a question of pigmentation: Red aphids tend to be consumed by ladybugs and green ones by parasitic wasps. Aphid color is determined by carotenoids, the same group of chemicals that make flamingos pink. But unlike flamingos, which have to eat colored food to stay pink, aphids make their own pigment. Carotenoids are vital to animals, not only because of their decorative possibilities but also for their oxidation-protective qualities as visual pigments and immune-system modulators. On sifting through an aphid genome, Moran and Jarvik (p. 624; see the Perspective by Fukatsu) discovered that the machinery for producing carotenoids has been acquired by an ancestral aphid in a lateral transfer event from a fungus. Although a spontaneous yellow mutant aphid was found that still possesses the sequence for biosynthesis of the red carotenoid pigment torulene, the sequence was discovered to have a single point mutation that puts a stop to turning red. An unusual case of ancestral transfer of pigment genes from a fungus confers a functionally specific trait in an animal. Carotenoids are colored compounds produced by plants, fungi, and microorganisms and are required in the diet of most animals for oxidation control or light detection. Pea aphids display a red-green color polymorphism, which influences their susceptibility to natural enemies, and the carotenoid torulene occurs only in red individuals. Unexpectedly, we found that the aphid genome itself encodes multiple enzymes for carotenoid biosynthesis. Phylogenetic analyses show that these aphid genes are derived from fungal genes, which have been integrated into the genome and duplicated. Red individuals have a 30-kilobase region, encoding a single carotenoid desaturase that is absent from green individuals. A mutation causing an amino acid replacement in this desaturase results in loss of torulene and of red body color. Thus, aphids are animals that make their own carotenoids.