Restriction enzyme analysis of the chloroplast and nuclear 45s ribosomal DNA of Allium sections Cepa and Phyllodolon (Alliaceae)

• Published in: Plant systematics and evolution 1992-01, Vol.183 (1/2), p.17-31
• Main Author: Havey, M.J
• Format: Article
• Language: English
• Subjects: Allium; analysis; Biological and medical sciences; Biological taxonomies; Chloroplast DNA; Chloroplasts; cladistic analysis; DNA; Enzymes; Fundamental and applied biological sciences. Psychology; Hybridity; Maximum parsimony; Onions; Phylogeny; Plant cytology, morphology, systematics, chorology and evolution; Plant evolution; Plants; restriction fragment length polymorphism; Ribosomal DNA; species; taxonomy
• ISSN: 0378-2697; 1615-6110
• DOI: 10.1007/BF00937732

Estimates of the phylogenetic relationships among cultivated and wild Allium species would benefit from identification of molecular characters. Restriction enzyme analysis of the chloroplast DNA (cpDNA) of the bulb onion (Allium cepa), Japanese bunching onion (A. fistulosum), wild Allium species in sect. Cepa and Phyllodolon, and the outgroups A. ampeloprasum and A. tuberosum detected 39 polymorphisms. Allium cepa and A. vavilovii were identical for all characters. Cladistic analysis generated three most-parsimonious Wagner trees of 44 steps differing only in a zero-length branch. Allium fistulosum and A. altaicum (sect. Phyllodolon) comprised a monophyletic lineage separated from the A. cepa and A. vavilovii of sect. Cepa. The unresolved node was composed of A. galanthum, A. roylei, and the lineage containing A. cepa, A. vavilovii, A. fistulosum, and A. altaicum. The clade containing A. altaicum, A. cepa, A. fistulosum, A. galanthum, A. roylei, and A. vavilovii remained resolved for strict consensus of Wagner trees of 48 steps or less. Allium pskemense and A. oschaninii were increasingly distant. Allium oschaninii has been proposed as the progenitor of the bulb onion, but was more closely related to the common progenitor of all species in sect. Cepa and Phyllodolon. Phylogenies estimated from cpDNA characters using Dollo parsimony resulted in a single most-parsimonious tree of 46 steps and agreed with phylogenies based on Wagner parsimony. Polymorphic restriction enzyme sites in the 45s ribosomal DNA were not used to estimate phylogenies because of uncertain homologies, but are useful for identifying interspecific hybrids. The maternal phylogenies estimated in this study help to distinguish wild Allium species closely related to the bulb onion. Although not in agreement with classifications based on morphology, the phylogenies closely reflected crossability among species in sect. Cepa and Phyllodolon.