Phylogenetic relationships in the family Amaryllidaceae

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Date
2005-12
Authors
Strydom, Adéle
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Publisher
University of the Free State
Abstract
English: The subject of this study is the family Amaryllidaceae with emphasis on 14 genera which represent six of the 15 tribes in this family. The genera are Amaryllis L., Ammocharis Herb., Boophone Herb., Brunsvigia Heist., Clivia Lindl., Crinum L., Crossyne Salisb., Cyrtanthus Aiton, Gethyllis L., Haemanthus, Hippeastrum, Narcissus L., Scadoxus Raf. and Strumaria Jacq. ex Willd. The Amaryllidaceae is a cosmopolitan, predominantly pantropical, family of petaloid, perennial or biennial monocots. The Amaryllidaceae form one of the climax groups in the Asparagales. They are probably more closely related to Alliaceae and Hyacinthaceae. The Amaryllidaceae is a large group consisting of about 860 species in 59 genera. Its centre of diversity is in Africa (19 genera) and South America (28 genera). Some genera also occur in the Mediterranean (8 genera) and temperate regions of Asia. Only one genus, Crinum L., is represented in both the Old and New Worlds because of seeds well adapted for dispersal over water. For this study a chloroplast gene and DNA region: matK and trnL-F, respectively, and a nuclear DNA region: ITS, were used in the phylogenetic reconstruction. All three give DNA sequences that are useful for comparing species and closely related genera. Despite a lack of consensus on generic limits and tribal delimitation within the Amaryllidaceae, cladistic analysis has only rarely been applied to problems in the family. Homoplasy for many conspicuous characters within some ge nera impedes the application of phylogenetic studies for the entire family. The combined trnL-F and matK matrix gave better results than the separate trnL-F analysis. The results of both the matK data and the combined matrix were well supported by bootstrap and jackknife. The sister status of the Eurasian/American/Mediterranean clades were better resolved in the separate matK analysis than the combined matrix. The indigenous tribes Amaryllideae, Haemantheae, Cyrtantheae and Gethyllideae were resolved and well supported in the separate matK and combined analysis. The results between the two combined matrices were very similar but the different tribes were better resolved in the combined matrix of all three DNA regions. In this study, the combined matrices indicated stronger bootstrap and jackknife support compared to the separate data sets of trnL-F, matK and ITS. Reported chromosome numbers of genera in the Amaryllidaceae indicates that variation between somatic chromosome numbers in each tribe is not high, except where hybridization may occur. Most of these somatic chromosome numbers agree with the given basic chromosome numbers that may occur in each tribe. As more becomes known of the southern African species in the family Amaryllidaceae, the lack of knowledge regarding chromosome morphology and behaviour becomes more apparent. In this study, the results of a cytogenetic study on several Cyrtanthus species are included. Chromosomes in this genus are large, as in the rest of the Amaryllidaceae. Variations in their karyotypes have been described. A somatic chromosome number of 2n = 2x = 16 was observed in most of the Cyrtanthus species except for two specimens of C. mackenii var. mackenii. A somatic chromosome number of 2n = 4x = 32 was indicated by these specimens. A tetraploid Cyrtanthus species has not been previously reported. However, this study did not support previous studies that ideograms vary among the different Cyrtanthus species and may be used in the identification of certain species. The variation in the ideograms was minimal and not sufficient for identification purposes. The results of this study strongly support those from previous studies and can be used in the classification of Amaryllidaceae.
Afrikaans: Die onderwerp van hierdie studie behels die familie Amaryllidaceae met klem op 14 genera wat ses van die 15 tribusse verteenwoordig in hierdie familie. Die genera is Amaryllis L., Ammocharis Herb., Boophone Herb., Brunsvigia Heist., Clivia Lindl., Crinum L., Crossyne Salisb., Cyrtanthus Aiton, Gethyllis L., Haemanthus, Hippeastrum, Narcissus L., Scadoxus Raf. en Strumaria Jacq. ex Willd. Die Amaryllidaceae is ‘n kosmopolitaanse, oorwegend pantropiese familie van kroonblaarvormige, meerjarige of tweejarige monokotiele. Die Amaryllidaceae vorm een van die klimaksgroepe in die Asparagales. Hulle is moontlik meer naverwant aan Alliaceae en Hyacinthaceae. Die Amaryllidaceae is ? groot groep wat bestaan uit ongeveer 860 spesies in 59 genera. Die middelpunt van diversiteit van hierdie familie is in Afrika (19 genera) en Suid -Amerika (28 genera). Sekere genera kom ook voor in die Mediterreen (8 genera) en matige gebiede van Asië. Net een genus, Crinum L., word verteenwoordig in beide die Ou en Nuwe Wêrelde vanweë saad wat goed aangepas is vir verspreiding oor water. Filogenetiese analise mag molekulêre data van nukleotiedvolgordes bevat om die klassifikasie van Amaryllidaceae tot in verskeie tribusse te evalueer. ? Chloroplastgeen en DNA-streek: matK en trnL-F, onderskeidelik, asook ? kern DNA-streek: ITS is gebruik in die filogenetiese rekonstruksie vir hierdie studie. Aldrie verskaf DNA-nukleotiedvolgordes wat nuttig is in die vergelyking van spesies en nabyverwante genera. Ongeag ? gebrek aan konsensus oor generiese limiete en tribusafbakening binne die Amaryllidaceae is kladistiese analise nog min toegepas op probleme in die familie. Homoplasie vir baie opvallende karakters binne sommige genera belemmer die toepassing van filogenetiese studies vir die hele familie. Die gekombineerde trnL-F en matK matriks het beter resultate gelewer as die aparte trnL-F analise. Die resultate van beide die matK-data en die gekombineerde matriks is goed ondersteun deur die steekproefhersteekproefnemingswaarde en J-uitsnit. Die susterstatus van die Eurasië/Amerikaanse/Mediterreense takke word beter verklaar in die aparte matK-analise as in die gekombineerde matriks. Die inheemse tribusse Amaryllideae, Haemantheae, Cyrtantheae en Gethyllideae word verklaar en goed ondersteun in die aparte matK- en gekombineerde analise. Die resultate tussen die twee gekombineerde matrikse was baie ooreenstemmend, maar die verskillende tribusse is beter verklaar in die gekombineerde matriks bestaande uit aldrie DNA-streke. Die gekombineerde matrikse het sterker steekproefhersteekproefnemingswaarde en J-uitsnit ondersteuning getoon in vergelyking met die aparte datastelle van trnL-F, matK en ITS in hierdie studie. Gepubliseerde chromosoomgetalle van genera in die Amaryllidaceae toon dat variasie tussen somatiese chromosoomgetalle in elke tribus nie hoog is nie, behalwe waar verbastering mag plaasgevind het. Meeste van hierdie somatiese chromosoomgetalle stem ooreen met die gegewe basiese chromosoomgetalle wat kan voorkom in elke tribus. Die gebrek aan kennis ten opsigte van chromosoommorfologie en –gedrag word meer opsigtelik soos nog inligting oor die suidelike Afrika-spesies in die familie Amaryllidaceae bekend word. Die resultate van sitogenetiese studie op verskeie Cyrtanthus-spesies word ingesluit by hierdie projek. Chromosome in hierdie genus is groot soos in die res van die Amaryllidaceae. Variasies in hulle kariotipes is al beskryf. Somatiese chromosoomgetal van 2n = 2x = 16 is waargeneem in meeste van die Cyrtanthus-spesies behalwe vir twee eksemplare van C. mackenii var. mackenii. ? Somatiese chromosoomgetal van 2n = 4x = 32 is getoon deur hierdie eksemplare. ? Tetraploïede Cyrtanthus-spesie is nog nie voorheen gerapporteer nie. Vorige studies wat aandui dat ideogramme varieer tussen die verskillende Cyrtanthus-spesies en gebruik kan word in die identifisering van verskeie spesies, word nietemin nie deur hierdie studie ondersteun nie. Die variasie in die ideogramme was minimaal en nie geskik vir identifikasiedoeleindes nie. Die resultate verkry in hierdie studie vergelyk baie goed met resultate verkry van vorige studies en kan gebruik word in die klassifikasie van Amaryllidaceae.
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Keywords
ITS region, DNA sequencing, MatK gene, Phylogenetic relationships, TrnL-F region, Chromosome numbers, Amaryllidaceae, Amaryllidaceae -- Cytogenetics, Thesis (Ph.D. (Plant Sciences: Genetics))--University of the Free State, 2005, Amaryllidaceae -- Phylogeny
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