0000000000729170
AUTHOR
Aaron Liston
Chloroplast DNA evidence for introgression and long distance dispersal in the desert annualSenecio flavus (Asteraceae)
Phylogenetic analysis of chloroplast DNA (cpDNA) restriction site variation supports a close genetic relationship between the Southwest AsianSenecio flavus subsp.breviflorus and the North AmericanS. mohavensis. The intercontinental disjunct distribution of these two desert annuals may have originated via long distance dispersal. The chloroplast genomes of the Southern and North AfricanS. flavus subsp.flavus and subsp.breviflorus differ by at least ten restriction sites, while at most two restriction sites differentiate the cpDNA genomes of subsp.breviflorus and the outgroupS. squalidus. This suggests that the cpDNA genome ofS. flavus subsp.breviflorus may have resulted from introgression an…
Repeat intercontinental dispersal and Pleistocene speciation in disjunct Mediterranean and desert Senecio (Asteraceae).
To explore the biogeographic history of Mediterranean/arid plant disjunctions, Old and New World Senecio sect. Senecio were analyzed phylogenetically using nuclear ribosomal DNA sequences (ITS). A clade corresponding to sect. Senecio was strongly supported. Area optimization indicated this clade to be of southern African origin. The Mediterranean and southern African floras were not distinguishable as sources of the main New World lineage, estimated to have become established during the middle Pliocene. Another previously suspected recent dispersal to the New World from the Mediterranean was confirmed for the recently recognized disjunction in S. mohavensis. The loss of suitable land connec…