The Journal of Heredity 1982:73(2):115-118
© 1982 The American Genetic Association 73:115-118
research-article |
The chromosomes of Nicotiana africana Merxm.: a recently discovered species
Department, North Carolina State University Raleigh. NC 27650
Abstract
The recent discovery of Nicotiana africana Merxm. extended the known natural distribution of the genus to another continent and generated considerable interest in this geographically isolated species. The chromosome complement (2n = 46) consists of two metacentric pairs and 21 pairs of acrocentrics. Four pairs organize nucleoli, but only two pairs have visible secondary constrictions. The distribution of heterochromatin and the karyotype show similarities with species of the Australian section of the genus, Suaveolentes, to which N. africana is related, and also to some American species. The asymmetrical karyotype suggests that the species has greatly diverged phylogeneticaily from the progenitor species of the genus.