Iris nelsonii (Iridaceae): Origin and Genetic Composition of a Homoploid Hybrid Species

Primer registro de un posible híbrido homoploide y de un tetraploide en el género Chaetanthera Ruiz & Pav. (Asteraceae) en Chile

“…Si bien la existencia de híbridos homoploides se conoce desde hace varias décadas (Randolph et al 1961, Randolph 1966, últimamente, han aumentado los estudios sobre este mecanismo de especiación (Arnold 1993, Buerkle et al 2000, Smith et al 2008, Masuelli et al 2009). …”

Hybrid fitness, adaptation and evolutionary diversification: lessons learned from Louisiana Irises

“…On the basis of morphological and chromosomal characteristics, Randolph (1966) described this species as a three-way hybrid derivative from natural crosses between I. fulva, I. brevicaulis and I. hexagona. Genetic markers from the nuclear and chloroplast genomes supported this inference, with alleles from each of the three species detected in the genome of I. nelsonii (Arnold, 1993). Whether the divergent ecological adaptations or distinctive morphological traits demonstrated by this species, relative to the progenitor taxa, are consequences of its hybrid origin has not yet been tested.…”

“…A second analysis involved the same backcross populations, but in this case, the genotypes were placed into southern Louisiana in regions occupied by native I. fulva, I. brevicaulis and natural hybrids (Viosca, 1935;Arnold, 1993;Johnston et al, 2001b). The microhabitats selected for transplants spanned hardwood forests (I. brevicaulis-like habitats; Viosca, 1935;Cruzan and Arnold, 1993;Johnston et al, 2001b) and bayous (I. fulva-like habitats; Viosca, 1935;Cruzan and Arnold, 1993;Johnston et al, 2001b).…”

“…Whether the divergent ecological adaptations or distinctive morphological traits demonstrated by this species, relative to the progenitor taxa, are consequences of its hybrid origin has not yet been tested. However, regardless of whether admixture has caused divergence in the various traits, this new lineage resulted from hybridization and introgression (Randolph, 1966;Arnold, 1993). Thus, as with cichlids, Drosophila, Homo and numerous other species clades, gene flow has continued during, and in the case of I. nelsonii, contributed to, the diversification and divergence of Louisiana Irises.…”

A report of hybridisation in Hymenachne (Poaceae, Panicoideae) with description of Hymenachne x calamitosa, a new species of hybrid origin from tropical Australia

“…Two of the most commonly used methods are the sequence comparisons of nuclear ribosomal DNA internal transcribed spacer (ITS) regions (Peterson et al 2009, Rauscher et al 2002, Aguilar et al 1999 and Random Amplified Polymorphic DNA (RAPD) assessments (Yüzbaşioğlu et al 2008, Lee et al 2006, González-Rodríguez et al 2004, Ayres et al 1999, Arnold 1993. We adopted both approaches in this study to provide clarity and confidence in the results.…”