DNA sequence variation in the fruit tree Inga inicuil (Leguminosae: Mimosoideae) from contrasting altitude distinguishes two different species

Abstract

<em>Inga inicuil</em> is a leguminous tree in Veracruz, Mexico whose fruits are locally commercialized. One taxonomic hypothesis suggests that <em>I. inicuil</em> is a species with a wide altitudinal range, while another segregates <em>I. paterno</em> from <em>I. inicuil</em> by altitude and morphology. DNA sequences from the nuclear ITS1-5.8S-ITS2 and the chloroplast <em>trn</em>L-F regions were used to explore the genetic variation between individuals of <em>I. inicuil </em>compare it with their altitudinal distribution and evaluate the possible relationship between altitude and sugar content in the fruits. Results indicated that sugar content is not related to altitude or with sequence variation. However, sequences from the <em>trn</em>L-F revealed an insertion/deletion of approximately 309 nucleotides present only in trees growing on the low-elevation coastal plain. Phylogenetic analyses with sequence data support the hypothesis that <em>I. inicuil</em> and <em>I. paterno</em> are two different species. The remarkable differences of sequence data from the <em>trn</em>L-F within the species make necessary further research increasing taxon sampling.