Biology subjects

Eguiarte, L. E.

Publications and source records attributed to Eguiarte, L. E..

3 recordsLinked to original sources

bioRxiv2018

The lost world of Cuatro Cienegas Basin, a relictual bacterial niche in a desert oasis.

Barriers to immigration can lead to localized adaptive radiations and increased endemism. We propose that extreme oligotrophy can be a strong barrier to immigration over geological timescales, and facilitate the evolution of diverse and coevolved microbial communities. We show here that the endangered oasis of Cuatro Cienegas Basin can be a model for a lost world, where the ancient niche of extreme oligotrophy favoured survival of ancestral microorganisms that persisted due to environmental stability and low extinction rates, generating a diverse and unique bacteria diversity. Diversification/extinction rates in Bacillus showed several CCB endemic clades that diverged from the rest of Bacillus spp. in different times of the Paleozoic and Mesozoic, in contrast to more recent Bacillus, Clostridium and Bacteroidetes lineages. CCB conservation is vital to the understanding of early evolutionary and ecological processes.

evolutionary biology↗

bioRxiv2017

Was maize domesticated in the Balsas Basin? Complex patterns of genetic divergence, gene flow and ancestral introgressions among Zea subspecies suggest an alternative scenario

The study of maize domestication has overlooked the genetic structure within maizes wild relative teosinte. Prior to investigating the domestication history of maize (Zea mays subspecies mays), one should first understand the population history of teosintes and how they relate to maize. To achieve this, we used 32,739 SNPs obtained from a broad sampling of teosinte populations and 46 maize landraces and a) inferred current and past gene flow among teosinte populations and maize, b) analyzed the degree of introgression among Zea mays subspecies, and c) explored the putative domestication location of maize. We found geographic structure and introgression between Zea mays taxa. Teosinte subspecies have diverged significantly from maize, which indicates that current teosinte populations have evolved mainly independently from maize since the domestication. Our results further suggest that the likely ancestor of maize may maybe have come from Jalisco or the Pacific coast.\n\nOne Sentence SummaryShared polymorphism in teosinte suggests a Jalisco origin of maize domestication.

evolutionary biology↗

bioRxiv2017

A new multi-genomic approach for the study of biogeochemical cycles at global scale: the molecular reconstruction of the sulfur cycle

Despite the great advances in microbial ecology and the explosion of high throughput sequencing, our ability to understand and integrate the global biogeochemical cycles is still limited. Here we propose a novel approach to summarize the complexity of the Sulfur cycle based on the minimum ecosystem concept, the microbial mat model and the relative entropy of protein domains involved in S-metabolism. This methodology produces a single value, called the Sulfur Score (SS), which informs about the specific S-related molecular machinery. After curating an inventory of microorganisms, pathways and genes taking part in this cycle, we benchmark the performance of the SS on a collection of 2,107 non-redundant RefSeq genomes, 900 metagenomes from MG-RAST and 35 metagenomes analyzed for the first time. We find that the SS is able to correctly classify microorganisms known to be involved in the S-cycle, yielding an Area Under the ROC Curve of 0.985. Moreover, when sorting environments the top-scoring metagenomes were hydrothermal vents, microbial mats and deep-sea sediments, among others. This methodology can be generalized to the analysis of other biogeochemical cycles or processes. Provided that an inventory of relevant pathways and microorganisms can be compiled, entropy-based scores could be used to detect environmental patterns and informative samples in multi-genomic scale.

bioinformatics↗