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United States Department of Agriculture

Agricultural Research Service

Research Project: CONSERVATION, CHARACTERIZATION, AND GENETIC IMPROVEMENT OF SUBTROPICAL AND TROPICAL ORNAMENTAL GERMPLASM

Location: Subtropical Horticulture Research

Title: Testing deep reticulate evolution in Amaryllidaceae Tribe Hippeastreae (Asparagales) with ITS and chloroplast sequence data

Authors
item Garcia, Nicolas -
item Meerow, Alan
item Soltis, Douglas -
item Soltis, Pamela -

Submitted to: Systematic Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 25, 2013
Publication Date: February 5, 2014
Citation: Garcia, N., Meerow, A.W., Soltis, D.E., Soltis, P.S. 2014. Testing deep reticulate evolution in Amaryllidaceae Tribe Hippeastreae (Asparagales) with ITS and chloroplast sequence data. Systematic Botany. 39:75-89.

Interpretive Summary: Using DNA sequences from the chloroplast and nucleus, a tree of life was inferred for the tribe Hippeastreae of the amaryllis family (Amaryllidaceae) using different statistical approaches. Conflicitng results among the different genes support an hypothesis of early hybridization among lineages in the tribe. All regions and analyses consistently inferred two major clades which are formalized as subtribes: A) Traubiinae, formed by Traubia, Placea, Phycella, Rhodolirium, and Famatina maulensis, characterized by x = 8, little polyploidy, and a round stigma, and B) Hippeastrinae, including Eithea, Habranthus, Haylockia, Hippeastrum, Rhodophiala, Sprekelia, Zephyranthes, and Famatina, characterized by a range of basic chromosome numbers (x = 6 – 11) and frequent polyploidy and aneuploidy. A brief description, generic circumscription, and geographic distribution are provided for each subtribe.

Technical Abstract: The phylogeny of Amaryllidaceae tribe Hippeastreae was inferred using chloroplast (3’ycf1, ndhF, trnL-F) and nuclear (ITS rDNA) sequence data under maximum parsimony and maximum likelihood frameworks. Network analyses were applied to resolve conflicting signals among data sets and putative scenarios of reticulate evolution. All regions and analyses consistently inferred two major clades which are formalized as subtribes: A) Traubiinae, formed by Traubia, Placea, Phycella, Rhodolirium, and Famatina maulensis, characterized by x = 8, rare polyploidy, and a capitate stigma, and B) Hippeastrinae, including Eithea, Habranthus, Haylockia, Hippeastrum, Rhodophiala, Sprekelia, Zephyranthes, and Famatina p.p., characterized by a range of basic chromosome numbers (x = 6 – 11) and frequent polyploidy and aneuploidy. No clear morphological features diagnose the latter clade, which contains ca. 90% of the tribe’s species diversity. Our phylogenetic results question the monophyly of all genera in the tribe and show widespread cytonuclear discordance within Hippeastrinae, further supporting putative ancient hybridization(s) preceding the radiation of this major clade. In contrast, the Chilean-Argentinean endemic Traubiinae shows a tree-like pattern of evolution, consistent with the absence of allopolyploidy observed in this clade. A brief description, generic circumscription, and geographic distribution are provided for each subtribe.

Last Modified: 10/1/2014
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