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A reexamination of the North American Crepis agamic complex and comparison with the findings of Babcock and Stebbins' classic biosystematic monograph.
Am J Bot. 2016 07; 103(7):1289-99.AJ

Abstract

PREMISE OF THE STUDY

Babcock and Stebbins coined the term agamic complex in their 1938 monograph of the North American Crepis agamic complex. Despite the historical role that this complex holds in the evolutionary literature, it has not been reexamined in over 75 years. We present a thorough reevaluation of the complex to test hypotheses proposed by Babcock and Stebbins about its origins and spread, the relationships of diploids, and the nature and origins of polyploids.

METHODS

We used flow cytometry to infer ploidy of roughly 600 samples spanning the morphological and taxonomic diversity of the complex and a phylogenetic analysis of plastid DNA variation to infer maternal relationships among diploids and to infer maternal origins of polyploids.

KEY RESULTS

We identified populations of all seven recognized diploids plus one new lineage. Phylogenetic analysis of plastid DNA variation in diploids revealed a well-resolved, but moderately supported phylogeny, with evidence for monophyly of the North America Crepis agamic complex and no evidence of widespread homoploid hybridization. Polyploids showed evidence of multiple origins and a pattern of frequent local co-occurrence consistent with repeated colonization of suitable sites.

CONCLUSIONS

Our findings agree broadly with the distribution and variation of ploidy within and among species described by Babcock and Stebbins. One key difference is finding support for monophyly of North American species, and refuting their hypothesis of polyphyly. Our results provide an explicit phylogenetic framework for further study of this classic agamic complex.

Authors+Show Affiliations

Department of Botany and Biodiversity Research Centre, The University of British Columbia, 3529-6270 University Boulevard, Vancouver, British Columbia V6T 1Z4 Canada fundywest@mac.com.Department of Botany and Biodiversity Research Centre, The University of British Columbia, 3529-6270 University Boulevard, Vancouver, British Columbia V6T 1Z4 Canada.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

27313196

Citation

Sears, Christopher J., and Jeannette Whitton. "A Reexamination of the North American Crepis Agamic Complex and Comparison With the Findings of Babcock and Stebbins' Classic Biosystematic Monograph." American Journal of Botany, vol. 103, no. 7, 2016, pp. 1289-99.
Sears CJ, Whitton J. A reexamination of the North American Crepis agamic complex and comparison with the findings of Babcock and Stebbins' classic biosystematic monograph. Am J Bot. 2016;103(7):1289-99.
Sears, C. J., & Whitton, J. (2016). A reexamination of the North American Crepis agamic complex and comparison with the findings of Babcock and Stebbins' classic biosystematic monograph. American Journal of Botany, 103(7), 1289-99. https://doi.org/10.3732/ajb.1600057
Sears CJ, Whitton J. A Reexamination of the North American Crepis Agamic Complex and Comparison With the Findings of Babcock and Stebbins' Classic Biosystematic Monograph. Am J Bot. 2016;103(7):1289-99. PubMed PMID: 27313196.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A reexamination of the North American Crepis agamic complex and comparison with the findings of Babcock and Stebbins' classic biosystematic monograph. AU - Sears,Christopher J, AU - Whitton,Jeannette, Y1 - 2016/06/16/ PY - 2016/02/07/received PY - 2016/04/12/accepted PY - 2016/6/18/entrez PY - 2016/6/18/pubmed PY - 2017/7/28/medline KW - Asteraceae KW - apomixis KW - flow cytometry KW - hybridization KW - multiple origins KW - plastid phylogeny SP - 1289 EP - 99 JF - American journal of botany JO - Am. J. Bot. VL - 103 IS - 7 N2 - PREMISE OF THE STUDY: Babcock and Stebbins coined the term agamic complex in their 1938 monograph of the North American Crepis agamic complex. Despite the historical role that this complex holds in the evolutionary literature, it has not been reexamined in over 75 years. We present a thorough reevaluation of the complex to test hypotheses proposed by Babcock and Stebbins about its origins and spread, the relationships of diploids, and the nature and origins of polyploids. METHODS: We used flow cytometry to infer ploidy of roughly 600 samples spanning the morphological and taxonomic diversity of the complex and a phylogenetic analysis of plastid DNA variation to infer maternal relationships among diploids and to infer maternal origins of polyploids. KEY RESULTS: We identified populations of all seven recognized diploids plus one new lineage. Phylogenetic analysis of plastid DNA variation in diploids revealed a well-resolved, but moderately supported phylogeny, with evidence for monophyly of the North America Crepis agamic complex and no evidence of widespread homoploid hybridization. Polyploids showed evidence of multiple origins and a pattern of frequent local co-occurrence consistent with repeated colonization of suitable sites. CONCLUSIONS: Our findings agree broadly with the distribution and variation of ploidy within and among species described by Babcock and Stebbins. One key difference is finding support for monophyly of North American species, and refuting their hypothesis of polyphyly. Our results provide an explicit phylogenetic framework for further study of this classic agamic complex. SN - 1537-2197 UR - https://www.unboundmedicine.com/medline/citation/27313196/A_reexamination_of_the_North_American_Crepis_agamic_complex_and_comparison_with_the_findings_of_Babcock_and_Stebbins'_classic_biosystematic_monograph_ L2 - https://doi.org/10.3732/ajb.1600057 DB - PRIME DP - Unbound Medicine ER -