Variation of Nuclear DNA Content in the Biflorus Species of Lonchocarpus (Leguminosae)

Abstract

This represents the first study of nuclear DNA content in a large sample (135 spp.) from a tropical arboreal genus, in which a large proportion of the species were examined (42 spp., 31.1%). Somatic chromosome numbers and 4C-DNA values for 51 taxa of Lonchocarpus are reported. All taxa were diploid with 2 n =22, but their DNA content ranged from 1.92 to 2.86 pg 4C nucleus, corresponding to a 48.95% variation in genome size. In the 74 collections studied, no correlation was observed between DNA content and habitat altitude. Variation in nuclear DNA content was analysed at the level of genus, subgenus, section and subsection. Variation in genome size was also studied within some species, either among widely separated populations or among different intraspecific taxa. Very little variation in genome size was detected between populations, subspecies, and varieties of the same species. The taxonomic implications of variation in nuclear DNA content are discussed.