DNA barcoding in amphitropical Larreas (Zygophyllaceae): a case of hybridization and chloroplast capture in sympatric populations. International Conference on DNA Barcoding and Biodiversity.

CASTELLO, L.V.; QUIROGA MP; C. P. SOUTO

Sofia

Congreso; ICDBB- International Conference on DNA Barcoding and Biodiversity; 2022

DNA barcoding assessments of floristic surveys from understudied geographic areas can enhance the development of regional barcoding libraries, providing vital data for community phylogeny construction and studies in ecology and conservation biology. This study aims to investigate the utility and species resolution capability of DNA barcoding in sympatric species known to hybridize. The genus Larrea provides an interesting system since it shows amphitropical distribution in North and South American deserts, and has paternal inherited chloroplasts. We analysed genetic patterns in both nuclear (ITS spacer) and chloroplast’ (gene rbcL) of Larrea tridentata in North America; and genotyped four South American congeners, Larrea divaricata, Larrea nitida, Larrea ameghinoi, and Larrea cuneifolia native to Monte Desert, the largest South American dryland. We performed phylogeographic analyses using individuals collected in populations along the total range of each species, including some overlapped populations. We aligned and analysed DNA sequences using haplotype trees and networks for each marker. The nuclear marker showed a genetically variable genus (29 haplotypes) and individualized each species, while showing traces of possible hybridization between L. cuneifolia and L. divaricata. L. divaricata, is the most genetically diverse taxon and is sister to L. tridentata. RbcL gene is less genetically variable (6 haplotypes), and suggested generalized chloroplast capture between L. nitida and L. cuneifolia, and localized between L. divaricata and L. cuneifolia. These results indicate that chloroplast capture and hybridization are widespread in this genus and confirm the usefulness of analyzing different types of genetic markers to identify species and understand evolutionary processes. Also highlighting the needed caveat when using barcoding genes in related plant species since they might reflect reticulated processes. These extended phenomena in plants maintained evolutionary lineages with a genetic mosaic and gave them resilience to face the changes that have occurred on the planet over millions of years.