Denisse Tellez Mazzocco

Instituto de Biotechnología

Education

Licenciatura en Biología, Universidad Autónoma del Estado de Hidalgo. 19 July 2006

Delimitación de especies del género Thalictrum (Ranunculaceae) del centro de México con base en caracteres morfológicos y moleculares.

Abstract

The delimitation of several species of Thalictrum from central Mexico is controversial. The purpose of this investigation is 1) to confirm the phylogenetic position of the Mexican species of Thalictrum within the andromonic clade and 2) to apply the phylogenetic species concept to investigate the validity of these species. DNA was extracted from individuals collected from central Mexico. The internal transcribed spacer (ITS) region of the ribosomal DNA was sequenced, and parsimony analysis was used to determine the position of the Mexican species relative to other species of Thalictrum from around the world. With respect to sexual systems, the Mexican taxa belong to a paraphyletic group of andromonoic species, the hermaphroditic species are polyphyletic, and dioecious species form two separate clades. The Mexican species form an unresolved polytomy in the strict consensus tree. Population aggregation analysis show that T. gibbosum differs from T. hernandezii in the morphology of the achene and T. pubigerum and T. strigillosum differ in the density of the indumentum of the lower surface of the leaflet. Comparisons between T. pubigerum and T. strigillosum revealed that the two species share the same ITS region in some populations.