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Evidence for the Polyphyly of Haworthia (Asphodelaceae Subfamily Alooideae; Asparagales) Inferred from Nucleotide Sequences of rbc L, mat K, ITS1 and Genomic Fingerprinting with ISSR‐PCR
Author(s) -
Treutlein J.,
Smith G. F.,
Wyk B.E.,
Wink M.
Publication year - 2003
Publication title -
plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 1435-8603
DOI - 10.1055/s-2003-44793
Subject(s) - polyphyly , biology , subgenus , monophyly , phylogenetic tree , botany , chloroplast dna , subfamily , clade , genus , genetics , gene
Four molecular markers have been studied to examine the phylogenetic position of the South African plant genus Haworthia Duval within the succulent Asphodelaceae. Sequence data of the chloroplast genes mat K and rbc L were compared to the nuclear markers ITS1 and ISSR (Inter Simple Sequence Repeat) analysis. Both lines of molecular data, chloroplast and nuclear DNA, indicate that Haworthia is polyphyletic, forming two distinct clades. Most taxa previously combined as Haworthia subgenus Haworthia branch off early in the alooid chloroplast trees forming a strongly monophyletic group, whereas subgenus Hexangulares forms a polyphyletic assemblage comprising other alooid genera. The nuclear markers ITS1 and ISSR fingerprinting support the two groups as distinctly different, therefore confirming the division seen in chloroplast DNA. The practical implication is that the generic concept of Haworthia may have to be restricted to H. subgenus Haworthia or alternatively, that the groups of Haworthia be treated as infrageneric taxa within a broadened (Linnaean) concept of Aloe.