I am just about the worst blogger ever this week.
I’ve been out in the field around Illinois taking new photos (see right sidebar!) and neglecting my internet… um, responsibilities? Procrastinations? Whatever you call it. In any case, it’s far past time to answer Monday’s mystery.
The DNA sequence was a fragment from a carotenoid desaturase gene isolated from the oleander aphid, Aphis nerii. The fragment was obtained as part of a phylogenetic study pinning the origin of such genes in aphids to an ancient acquisition from fungi. Of the photographs I showed, only one aphid (B) had the brilliant yellow coloration of Aphis nerii.
Carotenoids are common pigments in plants, fungi, and other organisms. The color of carrots, for example, is due to carotenoids. But these useful molecules are notably missing from animals. When carotenoids turned up unexpectedly in aphids, their origin was something of a mystery until Nancy Moran’s research group figured out that aphid ancestors had somehow subsumed fungal carotenoid genes. A natural instance of genetic engineering, as it were.
6 points go to bioczw for getting to the correct ID first, and 4 points go to Guillaume D. for the fungal link.
Moran NA, Jarvik T. 2010. Lateral transfer of genes from fungi underlies carotenoid production in aphids. Science 328: 624-627. DOI: 10.1126/science.1187113
Nováková E, Moran NA. 2012. Diversification of genes for carotenoid biosynthesis in aphids following an ancient transfer from a fungus. Mol Bio Evol. 29: 313-323. doi: 10.1093/molbev/msr206