Kobe University Repository : Kernel タイトル A review of chromosome numbers in the Asteraceae with hypotheses Title on chromosome base number evolution. 著者 Semple, John C./ Watanabe, Kuniaki Author(s) 掲載誌・巻号・ページ Systematics, evolution, and biogeography of Compositae,:61-72 Citation 刊行日 2009 Issue date 資源タイプ Book / 図書 Resource Type 版区分 publisher Resource Version 権利 Rights DOI JaLCDOI URL http://www.lib.kobe-u.ac.jp/handle_kernel/90001251 PDF issue: 2021-09-23 Chapter 4 A review of chromosome numbers in Asteraceae with hypotheses on chromosomal base number evolution John C. Semple and Kuniaki Watanabe INTRODUCTION more recent years following the introduction of molecu- lar techniques for analyzing phylogenies through DNA In spite of the great variability in the chromosome restriction fragment length polymorphisms and base pair numbers … a pattern can be seen when the evidence sequence analyses, authors have compared molecular is fully reviewed. — Robinson et al. 1981, p. 8 results with chromosomal basal number data in order to reach conclusions on ancestral base numbers within Asteraceae are the largest family of fl owering plants and groups of genera and among tribes (e.g., Baldwin et al. have long been of cytological interest. The fi rst chromo- 2002; Ito et al. 2000; Chapter 37). Accessing data in all some counts for members of the family were published of the tens of thousands of publications reporting chro- more than a century ago (Juel 1900; Land 1900; Merrell mosome numbers in Asteraceae has not been convenient 1900). The total number of chromosome number reports until very recently, when much of the information was has increased dramatically with major eff orts to determine put online in Watanabe’s (2008) Index to Chromosome chromosome numbers of large numbers of composites Numbers in Asteraceae (http://www.lib.kobe-u.ac.jp/prod being conducted in the 1960 –1980 period (e.g., Raven et ucts/asteraceae/index.html). This paper presents analyses al. 1960; Anderson et al. 1974). Prior to DNA sequence- of chromosome numbers in the online database in light based phylogenetic analyses, hypotheses on chromosomal of recent understanding of the phylogeny of Asteraceae base numbers in Asteraceae were hampered by a lack of (e.g., Funk et al. 2005). The fi rst objective of the study understanding of which genera were basal within tribes was to compile a summary database of every genus in and which tribes were basal within the family. For exam- the family. The second objective was to determine the ple, Cronquist (1981) reported that Asteraceae had a range chromosomal base number for every genus in the fam- of base numbers from x = 2 to x = 19+ and suggested ily for which data were available. The third objective that perhaps x = 9 was ancestral. Earlier, Solbrig (1977) was to plot chromosome counts and basal chromosome had also concluded x = 9 was the ancestral base number numbers of every taxon onto the supertree (= metatree) of the family based on an analysis of habit and frequency phylogeny (Funk et al. 2005). The fourth object was to of chromosome numbers. Bremer (1994) merely noted formulate hypotheses on patterns of chromosomal base that chromosome number data were conveniently sum- number evolution in the family having “fully reviewed” marized in Solbrig (1977) and subsequent indices. In the evidence. 62 Semple and Watanabe MATERIALS AND METHODS A database summarizing information by genus on chromosome number data was constructed using ask- Two datasets were used as primary sources of informa- Sam working from the Watanabe and Semple datasets tion on chromosome numbers. The most critical of these plus information in generic treatments in Flora of North were the data available online at http://www.lib.kobe-u America (vols. 19–21). Eighteen data fi elds were included .ac.jp/products/asteraceae/index.html, Watanabe’s Index for each genus document. These are listed in Table 4.1 to Chro mo some Numbers of Asteraceae (2008). The database and included data on nomenclature and numbers of spe- has been updated multiples times as data from addi- cies, number of chromosome number reports (actual or tional publications are added to the matrix. Our analysis estimated total number of counts), a list of chromosome is based on entries in the database as of March 2007. numbers reported in the literature, ancestral and derived This included records on more than 38,000 chromosome base numbers determined in this study, other cytological number reports at the time of our analysis listed by author data (ploidy levels, aneuploidy, dysploidy and supernu- and taxon; and 41,000 as of September 2007. Each search merary chromosomes), geographic distribution informa- of counts in a genus included a summary of the number tion, and a fi eld for miscellaneous observations, e.g., al- of reports, but not a calculated total of the actual numbers ternative sources of data, etc. of counts included in the records. When a publication The completed generic summary database was searched reported multiple counts for a single taxon, these were to generate reports on a number of diff erent cytological not listed separately. However, the information could be and taxonomic questions. Lists of genera with cytologi- tallied from data presented in the search results. Also, cal data were generated for each tribe, subtribe or clade. searches for some genera include the names of taxa for Separate lists of all genera sorted alphabetically, by chro- which no chromosome counts have been reported in the mosomal base number, and by numbers of reports were literature. Thus, the number of “records” listed at the also generated. Reports were saved as *.ask fi les, which top of a search report needed to be recalculated to yield can be exported as *.txt, *.rtf, *.html and several other the actual number of individual chromosome number fi le formats. reports for a genus included in the summary data matrix created for this paper. The Watanabe dataset included data extracted from 4521 publications at the time of our RESULTS AND DISCUSSION analysis, and 4800 as of September 2007. Details on these can be accessed from the search reports generated by the Data on 1587 genera of Asteraceae and 15 genera of web site and are not listed here. Searches of the database Calyceraceae and Goodeniaceae were included in the ge- for this chapter were facilitated by working off -line di- neric summary database. The results of analyses of num- rectly from the Microsoft Excel™ data fi le (*.xls) created bers of counts and reports by genus are summarized by by Watanabe. Generic nomenclature in the Watanabe tribe/clade in Table 4.2 listed in the order of branching of database follows Bremer (1994) with post March 2007 clades on the supertree phylogeny of Funk et al. (2005). changes to refl ect treatments of taxa in Flora of North Included in Table 4.2 by tribe/clade are the numbers of America (Flora of North America Editorial Committee genera included in this study compared with the number 2006). of genera reported for each tribe/clade in Bremer (1994), The second data source for chromosome counts was the percent of genera with at least one chromosome num- the fi rst author’s research database fi les on chromosome ber report, an estimate of the number of species, and an number reports for asters, goldenrods and miscellaneous estimate of the number of count reports. other genera of Astereae (primarily taxa of the subtribe An estimated 58,320 chromosome number reports were Chrysopsidinae Nesom and miscellaneous other North summarized; 58,124 of these reports were for Asteraceae. American Astereae). The Semple datasets collectively The actual number of chromosome number count deter- included information on 10,835 individual counts at minations made on individuals is not known because this the time of our analysis and are based on individual information was not always included in a publication. In voucher data. These were compiled for research on cyto- some cases, a report was based on a chromosome count geographic and taxonomic studies. Nomenclature in the from a single individual of a taxon. In other cases, several Semple databases follows that of generic treatments of hundred to more than a thousand counts were reported the Asteraceae in Flora of North America (vols. 19–21) with for a single taxon in one publication (e.g., Semple 1989). a data fi eld indicating the name under which the count Papers reporting very large numbers of counts ( > 100) was originally published. These datasets are not avail- for a taxon were usually cytogeographic studies. At least able online. Each of the data fi les (*.ask) was created in one chromosome count has been reported for a taxon in askSam™ v.5.1.2.367 (Seaside Software Inc. dba askSam 978 genera of Asteraceae (61.6%); no data were available Systems, Perry, Florida). for 611 genera in the family. Thirteen genera were found Chapter 4: A review of chromosome numbers in Asteraceae 63 to have more than 1000 chromosome number reports at the time our analysis was fi rst completed and involves in total ( Table 4.3). The majority of genera have ten or the two authors of this paper. In the Watanabe database fewer chromosome number reports (598 genera; 37.7%); in March 2007, counts for asters were generally listed 203 genera (12.8%) have been sampled only once. in the genus Aster L. under which the majority of the The number of species of composites is estimated to counts were originally reported. The online index con- be 22,472 (= total of all estimated numbers of species by tained 1753 records for Aster s.l. and one record for the genus) in 1587 genera.