Evaluación y comparación del ADN extraído de especímenes vegetales provenientes de diferentes zonas de vida de Colombia

Abstract

Tissue collection for DNA extraction has become a common practice when making botanical collections. However, little is known about the possible degradation that DNA undergoes from the moment of collection of the botanical specimen until the tissue is taken to subject it to a rapid dehydration process, a time that can vary from a few minutes, if done immediately, up to about 12 hours, when the specimen is mounted on newsprint. Considering that tissue banks for DNA extraction must preserve them in perpetuity, it is important that the practices we use today are adequate to ensure DNA of optimal quality and purity. In order to evaluate whether the concentration and purity of the DNA extracted from the tissues vary with the altitude, precipitation, and temperature of the collection area, the DNA extracted from 3,356 plant specimens from 18 permanent plots located in seven life zones was evaluated. , in ten departments of Colombia. The study correlated climatic factors such as precipitation, temperature, and altitude, with the concentration and purity of the DNA obtained. When comparing the concentration of DNA from different life zones, it was shown that the highest concentrations were obtained in samples from the plots located in the Humid Montane Forest and Humid Premontane Forest life zones. Likewise, the concentration obtained from tissues from the Moist Montane Forest, Premontane Moist Forest, and Tropical Dry Forest life zones showed significant differences from those of the Moist Forest and Very Humid Tropical Forest. In the same way, it was found that at higher altitudes (masl), a higher concentration of DNA was obtained, while in those areas with higher values ​​of precipitation and temperature, lower concentrations were obtained. Regarding purity, in most of the extractions carried out DNA of very low purity was obtained, and although a tendency was found to find higher DNA purity in samples from the Humid Montane Forest and Premontane Humid Forest, as well as a positive correlation with altitude, the statistics used do not rule out chance as the main cause of the differences in purity values ​​in the samples studied. Based on the results, we can conclude that the practice of collecting tissues for DNA extraction hours after the specimen has been collected can be carried out in areas of the montane and premontane humid forests without affecting the quality of the DNA, but in the other areas of life studied (bmh-MB, bh-T, bmh-T, bs-PM, and bs-T), the tissue must be collected in the field, simultaneously with the collection of the botanical specimen.