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Phylogenetic Analysis of Monocotyledons (monocot/ Liliopsida ) by Anne Katchy 10/28/2009. One of the two major groups of Angiosperm. Flowering plants. Characteristics: - Single cotyledon -Pollen with single pore -Flower parts in multiples of three -Major leaf vein runs parallel
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Phylogenetic Analysis of Monocotyledons (monocot/Liliopsida)byAnne Katchy10/28/2009
One of the two major groups of Angiosperm. • Flowering plants. • Characteristics: -Single cotyledon -Pollen with single pore -Flower parts in multiples of three -Major leaf vein runs parallel -Stem vascular bundles scattered -Adventitious roots -No secondary growth. Monocots (Liliopsida):
Acorus (Sweet Flag) • Tofieldiaceae (Scottish asphodel) • Araceae (aroids) • Alismatales (Aquatics e.g. pondweeds) • Pandanales (Screwpines) • Liliales (Lilies and tulips) • Dioscoreales + Nartheciaceae ( yam and bog asphodel) • Asparagales (Irises and orchids) • Arecaceae (palms) • Dasypogonaceae (dasypogonoids) • Commelinales + Zingiberales (spiderworts and gingers). • Bromeliaceae + Rapateaceae (bromeliads) • Sparganium + Typha (bur-reeds and cat-tails) • Poales (grasses and sedges) Cont’d…..
Monocots are considered a monophyletic group. • Originated in the early Cretaceous. • 65,000 species, 91 families, and 12 orders, and including such groups as grasses, palms, gingers, orchids, lilies, and yams. • Most diverse, morphologically varied, ecologically successful (e.g. grass), and economically important (e.g. corn, rice, wheat, and barley) of the early clade of angiosperm. Phylogenetic view: Facts from studies:
Longer branch lenghts among some taxa when compared to others– change rates are unequal. • Phylogenetic dating – showing the ages of these orders and may be a reason as to why certain characteristics are lost when observed starting from the basal groups. • Uncertainty regarding the number of early Cretaceous clades especially within Poales and Alismatales. Cont’d….
Multi-gene and genomic approaches (sequencing), and database searches. • Analysis of data using parsimony, Bayesian, and maximum-likelihood methods (maximum-parsimony method for phylogenetic reconstruction). • Bootstrapping/Consensus tree. • Pairwise sequence comparison. Methods:
How can we recognize the taxa of angiosperm, given that some monocots have features of dicots?, Also the position of monocots within the angiosperm. • There are several classification methods used for angiosperms leading to varying numbers of subclasses and orders. What universal method can be used as a reliable system of classification? • Challenges involved in the clarification of the relationship within the monocots using morphological and molecular data. • Understanding their origin, phylogeny, and patterns of morphological divergence, geographic diversification, and ecological radiation. Questions/Challenges:
Kae Bremer. Early Cretaceous lineages of monocot flowering plants. Proc Natl Acad Sci. 2000 April 25; 97(9): 4707-11. Tamaru et al. Molecular phylogeny of monocotyledons inferred from combined analysis of plastid matK and rbcL gene sequences. J Plant Res (2004) 117: 109-120. Assembling the phylogeny of Monocots. http://botany.wisc.edu/monatol Zarrei et al. Molecular systematics of Gagea and Lloydia (Liliaceae; Liliales): implications of analyses of nuclear ribosomal and plastid DNA sequences for infrageneric classification. Ann Bot. 2009 Jul; 104(1): 125-42. Chase et al. Higher-level systematics of monocotyledons: an assessment of current knowledge and a new classification. CSIRO 2000. pp 3-16. References: