Biology subjects

Gasca-Pineda, J.

Publications and source records attributed to Gasca-Pineda, J..

6 recordsLinked to original sources

bioRxiv2024

Feminization of the precarious at the UNAM: examining obstacles to gender equality

The STEM workforce is marked by the persistent underrepresentation of women. Herein we seek a better understanding of this gender gap in different science disciplines within Latin America. Specifically, we analyzed the professional development of women in science research institutions of the National Autonomous University of Mexico (UNAM). Our analysis deepened how horizontal and vertical segregation are combined with symbolic and structural obstacles, as well as economic labor precariousness, within the framework of gender norms. We explored shared trends in the Global North to explore the perpetuation of gender stereotypes in the production of scientific knowledge; and investigated the relationship between the values implied in gender norms and the cultural capital represented in each of the disciplines. As a result, we evidenced that the knowledge areas that currently represent the highest cultural capital (pSTEM) mainly pose symbolic (and less structural) obstacles for women. Conversely, women in fields with less masculine-coded values face mainly structural barriers. This information sheds light on the gender biases that exclude women from STEM.

scientific communication and education↗

bioRxiv2023

Divergent lineages in a young species: the case of Datilillo (Yucca valida), a broadly distributed plant from the Baja California Peninsula

PremiseGlobally, barriers triggered by climatic changes have caused habitat fragmentation and population allopatric divergence. Across North America, oscillations during the Quaternary have played important roles in the distribution of wildlife. Notably, diverse plant species from the Baja California Peninsula, in western North America, exhibit strong genetic structure and highly concordant divergent lineages across their ranges, as they were isolated during the Pleistocene glacial-interglacial cycles and thus accumulated genetic differentiation in their genomes. A representative plant genus of this Peninsula is Yucca, with Yucca valida having the widest range. Whereas Y. valida is a dominant species, there is an extensive distribution discontinuity between 26{degrees} N and 27{degrees} N, where no individuals have been identified, suggesting restricted gene flow. Moreover, the historical distribution models indicate the absence of an area with suitable conditions for the species during the Last Interglacial, making it an interesting model for studying genetic divergence. MethodsWe examined the phylogeography of Y. valida throughout its range to identify the number of genetic lineages, quantify their genetic differentiation, reconstruct their demographic history and estimate the species age. Key resultsWe assembled 4,411 SNPs from 147 plants, identifying three allopatric lineages. Our analyses support that genetic drift is the driver of genetic differentiation among these lineages. We estimated an age under one million years for the common ancestor of Y. valida and its sister species. ConclusionsHabitat fragmentation caused by climatic changes, low dispersal, and an extensive geographical range gap acted as cumulative mechanisms leading to allopatric divergence in Y. valida.

evolutionary biology↗

bioRxiv2021

Strengthened mutualistic adaptation between teosinte and its rhizosphere biota in cold climates

O_LIWhile abiotic environments consistently shape local adaptation, the strength of local adaptation to biotic interactions may vary more. One theory, COCO (CO-evolutionary Outcomes across Conditionality), predicts it may be strongest where species experience greater stress, because stress increases fitness impacts of species interactions. For example, in plant interactions with rhizosphere biota, positive outcomes increase with stress from low soil fertility, drought and cold. C_LIO_LITo investigate the influence of abiotic stress gradients on adaptation between plants and rhizosphere biota, we used a greenhouse common garden experiment recombining teosinte, Zea mays ssp. mexicana (wild relative of maize), and rhizosphere biota, collected across a stress gradient (elevational variation in temperature, precipitation, and nutrients). C_LIO_LIWe found stronger local adaptation between teosinte and rhizosphere biota from colder, more stressful sites, as expected by COCO. However, biota from less stressful, warmer sites provided greater average benefits across teosinte populations. Links between plant traits and 20-element profiles of plant leaves explained fitness variation, persisted in the field, were influenced by both plants and biota, and largely reflected patterns of local adaptation. C_LIO_LIIn sum, we uncovered greater local adaptation to biotic interactions in colder sites, and that both plants and rhizosphere biota affect the expression of plant phenotypes. C_LI

evolutionary biology↗

bioRxiv2021

Ecological relevance of abundant and rare taxa in a high-diverse elastic hypersaline microbial mat, using a small-scale sampling

We evaluated the microbial diversity and metabolome profile of an uncommon hypersaline elastic microbial mat from Cuatro Cienegas Basin (CCB) in the Chihuahuan Desert of Coahuila, Mexico. We collected ten samples on a small scale transect (1.5-meters) and described its microbial diversity through NGS-based ITS and 16S rDNA gene sequencing. A very low number of taxa comprised a considerable proportion of the mat and were shared across all sampling points, whereas the rare biosphere was more phylogenetically diverse (Faiths Phylogenetic Diversity (FPD) index) and phylogenetically disperse (using a null model distribution of Phylogenetic Species Clustering (nmdPSC)) than the abundant (high read count) taxa for both analyzed libraries. We also found a distinctive metabolome profile for each sample and were able to tentatively annotate several classes of compounds with relevant biological properties.

microbiology↗

bioRxiv2020

Evaluation of the minimum sampling design for population genomic and microsatellite studies. An analysis based on wild maize.

Massive parallel sequencing is revolutionizing the field of molecular ecology by allowing to understand better the evolutionary history of populations and species, and to detect genomic regions that could be under selection. However, the needed economic and computational resources generate a tradeoff between the amount of loci that can be obtained and the number of populations or individuals that can be sequenced. In this work, we analyzed and compared two extensive genomic and one large microsatellite datasets consisting of empirical data. We generated different subsampling designs by changing the number of loci, individuals, populations and individuals per population to test for deviations in classic population genetics parameters (HS, FIS, FST) and landscape genetic tests (isolation by distance and environment, central abundance hypothesis). We also tested the effect of sampling different number of populations in the detection of outlier SNPs. We found that the microsatellite dataset is very sensitive to the number of individuals sampled when obtaining summary statistics. FIS was particularly sensitive to a low sampling of individuals in the genomic and microsatellite datasets. For the genomic datasets, we found that as long as many populations are sampled, few individuals and loci are needed. For all datasets we found that increasing the number of population sampled is important to obtain precise landscape genetic estimates. Finally, we corroborated that outlier tests are sensitive to the number of populations sampled. We conclude by proposing different sampling designs depending on the objectives.

genomics↗

bioRxiv2019

The role of historical and contemporary environmental factors in the distribution of genetic diversity in the teosinte in Mexico

Wild maize, commonly known as teosinte, has a wide distribution in central Mexico and inhabits a wide range of environmental conditions. According to previous studies, the environment is a determinant factor for the amount and distribution of genetic diversity. In this study, we used a set of neutral markers to explore the influence of contemporary factors and historical environmental shifts on genetic diversity, including present and three historical periods. Using a set of 22 nuclear microsatellite loci, we genotyped 527 individuals from 29 localities. We found highly variable levels of genetic diversity (Z. m. parviglumis HE= 0.3646-0.7699; Z. m. mexicana HE= 0.5885-0.7671) and significant genetic structure among localities (average DEST= 0.4332). Also, we recovered significant values of heterozygote deficiency (average FIS= 0.1796) and variable levels of selfing (sg2=0.0-0.3090). The Bayesian assignment analysis yielded four genetic clusters dividing the sample into subspecies, that in turn, were separated into two clusters. Environmental conditions played a strong influence in the distribution of genetic diversity, as demographic analysis and changes in species range revealed by modeling analyses were consistent. We conclude that current genetic diversity in teosinte is the result of a mixture of local adaptation and genetic isolation along with historical environmental fluctuations.

evolutionary biology↗