Genetic relationships among American species of the genus Prosopis (Mimosoideae, Leguminosae) inferred from ITS sequences: evidence for long‐distance dispersal

Abstract

Aim The genus Prosopis includes 44 species and has a pseudoamphitropical, disjunct distribution. We aimed to determine whether American Prosopis sections arose in North or South America, and to explain the current distribution of their species on the basis of their genetic relationships. Location South‐western USA, Mexico, Caribbean Antilles, Peru–Ecuador, central and northern Argentina, south‐western Argentina (Patagonia) and Cuyo, south‐western Asia and northern Africa. Methods Internal transcribed spacer fragments from 21 species of Prosopis were sequenced and the data were used to analyse the phylogenetic relationships using Microlobius and Mimosa as outgroups. Genetic distances were calculated to estimate the degree of divergence. Dispersal–vicariance (DIVA) analysis was conducted to help understand the biogeographical history of the genus. Main conclusions The sections Strombocarpa and Algarobia are not monophyletic. Prosopis argentina (section Monilicarpa) and the species of Algarobia are included in single clade. The phylogeny, DIVA analysis, and the pattern of genetic distances indicate that the ancestral area for the American species was wide, from south‐western USA to Central and northern Argentina. Successive vicariance events split this area, and long‐distance dispersal episodes (perhaps mediated by birds) led to recolonizations from North to South America, and vice versa.

Consistency of population genetics parameters estimated from isozyme and RAPDs dataset in species of genus Prosopis (Leguminosae, Mimosoideae)

“…The main discrepancies between the phenograms are due to the position of hybrid populations and P. vinalillo. The similarity between P. vinalillo and P. ruscifolia born out of the RAPDs tree is consistent with a cladistic analysis based on ITS sequence (Bessega et al 2006). However, the taxonomic status of P. vinalillo is under debate.…”

“…The population analyzed here (7 de Abril) fits the description by Burkart (1976) of the type specimen, but R. Palacios (personal communication) claims that in most population samples individuals identified as P. vinalillo are in fact hybrids or introgressants involving P. ruscifolia as one parent. However, the ITS sequence of P. vinalillo from 7 de Abril is significantly differentiated from both P. ruscifolia and P. alba (Bessega et al 2006), suggesting that P. vinalillo is not just a hybrid. The final answer on the status of P. vinalillo requires the analysis of a higher number of DNA sequences to avoid bias attributable to gene sampling.…”

RAPD and microsatellite transferability studies in selected species of Prosopis (section Algarobia) with emphasis on Prosopis juliflora and P. pallida

“…The clustering pattern of the Prosopis species selected in this work does not agree with the morphological criteria proposed by Burkart (1976), since species of the same series are not clustered together. There seems to be incongruence between the morphological and molecular data in the case of Prosopis species analysed here, and similar inconsistency was also observed in previous studies by many authors (Saidman and Vilardi 1987;Bessega et al 2005Bessega et al , 2006.…”

Características evolutivas en Prosopis spp.: citogenética, genética e hibridaciones

“…Se ha sugerido que este país es el principal centro de dispersión de Prosopis en América y que el mexicano-texano es secundario (Tapia Pastrana et al 1999). El análisis de reconstrucción biogeográfica DIVA (dispersalvicariance analysis) y el patrón de distancias genéticas indicarían que el área ancestral para las especies americanas abarcaría desde el suroeste de Estados Unidos hasta el centro y norte de Argentina; sucesivos eventos de vicariancia dividirían esta área y episodios de dispersión a larga distancia (mediados por aves) llevaron a recolonizaciones del Norte a América del Sur y viceversa (Bessega et al 2006). No obstante, la influencia humana -que incluye introducciones intencionales, invasiones de malezas y deforestación durante los últimos 500 años -ha alterado significativamente la distribución de especies de Prosopis, determinando su desaparición en ciertas áreas así como su inserción en India, Pakistán y Australia (Fig.…”