Eudicot paleohexaploidy

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Syntenic dotplot of grape versus itself. Each genomic region of grape is syntenic with two other intragenomic regions. This is evidence that grape is an ancient hexaploid. This hexaploid nature of its genome is shared with all other rosids and asterids (nearly the entire eudicot group). This analysis can be regenerated at: http://genomevolution.org/r/4p71

This event refers to the paleohexaploid origins of all sequenced eudicots to date, sampled from the eurosids and asterids. The ancestor to the radiation of these lineages was a hexaploid. The first published evidence for this came from the syntenic analysis of the grape genome [1]. The syntenic dotplot of grape's genome to itself showed that each region of its genome was syntenic to two other intragenomic regions. This can be most easily and parsimoniously explained if grape was an ancient hexaploid. Further analysis showed that this event was shared in all other sequenced rosid genomes, and subsequently in asterid genomes.

Other genomes that have not had a whole genome duplication event since the euidicot paleohexaploidy are:

  1. Carica papaya (papaya tree) (this genome is in a poor state of assembly and coverage (~3x)[2]


Please see plant paleopolyploidy for a figure and description of known plant paleoploidy events.

References:

  1. Jaillon, O., Aury, J., Noel, B., Policriti, A., Clepet, C., Casagrande, A., Choisne, N., Aubourg, S., Vitulo, N., Jubin, C., Vezzi, A., Legeai, F., Hugueney, P., Dasilva, C., Horner, D., Mica, E., Jublot, D., Poulain, J., Bruyère, C., Billault, A., Segurens, B., Gouyvenoux, M., Ugarte, E., Cattonaro, F., Anthouard, V., Vico, V., Del Fabbro, C., Alaux, M., Di Gaspero, G., Dumas, V., Felice, N., Paillard, S., Juman, I., Moroldo, M., Scalabrin, S., Canaguier, A., Le Clainche, I., Malacrida, G., Durand, E., Pesole, G., Laucou, V., Chatelet, P., Merdinoglu, D., Delledonne, M., Pezzotti, M., Lecharny, A., Scarpelli, C., Artiguenave, F., Pè, M., Valle, G., Morgante, M., Caboche, M., Adam-Blondon, A., Weissenbach, J., Quétier, F., & Wincker, P. (2007). The grapevine genome sequence suggests ancestral hexaploidization in major angiosperm phyla Nature, 449 (7161), 463-467 DOI: 10.1038/nature06148
  2. Ming R, Hou S, Feng Y, Yu Q, Dionne-Laporte A, Saw JH, Senin P, Wang W, Ly BV, Lewis KL, et al. The draft genome of the transgenic tropical fruit tree papaya (Carica papaya Linnaeus). Nature. 2008;452:991–996. doi: 10.1038/nature06856.