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Taxonomy
is of extreme importance for the classification of plant species. Nowadays, however, scientists are able to study the molecular structure and evolving relations of species through molecular biology , which is why the genetic bar code is a useful tool to learn more about plants, according to specialist Cindy Estrada Hernández from the Faculty of Chemistry at the National Autonomous University of Mexico (UNAM) .
Furthermore, genetic bar codes have been used to analyze food traceability aspects, that is to say, identify the origin of a food’s ingredients, as well as an overall health monitoring throughout the production chain to the point of dispensation.
A genetic bar code is a tool which allows for identifying animal or plant species by using a DNA segment of their genome . The segment is a partial sequence of a single gene which is taken from a living being’s genome.
In the case of plants, sequences chosen as reference come from the matK and rbcL genes, which are shared by all plants on earth. It should be noted that, in order to identify a species, scientists may use leafs, stems, seedlings, seeds, and even fragmented organisms.
Genetic bar codes for plants and animals can be found in the BOLD Systems database , created in 2005 by the Guelph University of Canada . In Mexico , there is a network called MexBOL which is currently working to generate bar codes for species in the national territory.
Quelite identification
Mexico is one of the 17 mega-biodiverse countries in the world , hosting over 23 species of vascular plants , including quelites, which have been used as food since pre-Hispanic times . However, their culture and consumption has progressively decreased through the years.
Specialist Estrada Hernández generated biologic bar codes for three species of quelites: chaya, alache, and chepil , as part of her project to rescue undervalued species from the traditional Mexican diet, aiming to contribute to the betterment of nutrition in Mexico.
When obtaining genetic bar codes for these species it is possible to access important information related to food traceability, contributing to the enhancement of the genetic bar codes database from Canada (BOLD) and providing an important information source for the preservation of agrobiodiversity on the long term, stated the academic.
Lastly, she explained that in order to generate a bar code for a plant species it is necessary to collect the sample, be it from the species’ natural habitat, herbaria, seed banks, frozen samples, etc. Furthermore, the DNA must be extracted from the biologic material to be replicated through PCR amplification (a molecular technique that replicates the gene) . The segment is then sequenced and a special software is later used to obtain the bar code which is later added to the database.
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