KOLTERMAN, DUANE A.1* and HARVEY E. BALLARD2. 1Dept. of Biology, University of Puerto Rico, Mayaguez, PR 00681-9012; 2Dept. of Environmental and Plant Biology, Ohio University, Athens, OH 45701. - Genetic diversity and affinities of Caesalpinia monensis Britton in the Greater Antilles based on ISSR markers.
Caesalpinia L. (Leguminosae: Caesalpinioideae) is a genus of
some 150 species of spiny or unarmed trees, shrubs, and climbers of
the Old World and New World tropics and subtropics. About 40 native
species and several introduced species are reported for the West
Indies, and about 30 species are cited as endemic to a single island
or archipelago. Caesalpinia monensis Britton is restricted to
two small populations on Mona Island, Puerto Rico; the species has
been under study for several years by Gary J. Breckon and the first
author in collaboration with the U.S. Fish and Wildlife Service,
Caribbean Field Office. To investigate its genetic diversity and
possible relationships in the Greater Antilles, the technique of ISSR
(Inter-Simple Sequence Repeat) markers was applied to population
samples of leaf material of C. monensis as well as samples of
C. bonduc (L.) Roxb. (from Mona Island), C. buchii Urb.
and C. domingensis Urb. (from the Dominican Republic), and
C. pauciflora (Griseb.) C.Wright (from the Dominican Republic
and Cuba). Following a preliminary screening, four primers were
selected and yielded a total of 47 DNA fragment bands among a total of
33 plant samples. UPGMA cluster analysis, neighbor-joining, and
principal coordinates ordination using a DICE similarity matrix from
band presence/absence data demonstrate that C. monensis
exhibits some genetic variability; the two populations intermingle,
sharing many ISSR bands, suggesting either active gene flow between
them or the retention of historic polymorphisms from a continuous past
distribution. Caesalpinia monensis is very close to C.
domingensis, and the two may not represent distinct species.
Caesalpinia pauciflora samples from the Dominican Republic and
Cuba are more or less well separated, and this species shows an
affinity to C. buchii. The scrambling, widespread C.
bonduc is distinct from the other species, which are erect Greater
Key words: Caesalpinia monensis, endemic, genetic diversity, Greater Antilles, ISSRs, Leguminosae