Biology subjects

Pinero, D.

Publications and source records attributed to Pinero, D..

3 recordsLinked to original sources

bioRxiv2025

Diversity and genetic structure within a Mexican maize race reveal consistent biocultural processes across geographic scales.

Understanding how genetic diversity is distributed within maize races is critical for conserving maize genetic diversity. While maize races are traditionally treated as homogeneous units to be targeted by conservation, each race may encompass genetically distinct populations of landraces, shaped by environmental conditions and farmer selection. In this study, the genetic diversity and population structure of the Olotillo race were examined using 89,810 SNPs from 158 samples collected across local, regional, and national scales in Mexico. Additional samples from other races Dzit-bacal, Tuxpeno, and a Mix, group combining Olotillo with other varieties, brought the total to 171 individuals. Population structure analyses (ADMIXTURE, PCA) revealed that genetic clusters do not align with race identity, but instead reflect geographic origin. Inbreeding depression was evident within Olotillo populations, with mean FIS = 0.746 {+/-} 0.066. A heterozygote deficiency was observed: mean HeOB = 0.075 {+/-} 0.020, compared to a higher expected heterozygosity (HeEX = 0.295 {+/-} 0.002). Expected homozygosity (HOEX) of 0.705{+/-} 0.002 was observed, reflecting reduced effective genetic variation. The above is reflected in the population contraction signal (e.g., positive Tajimas D), and no significant differences between scales in HeEX, HOEX, and nucleotide diversity ({pi}), suggesting that similar evolutionary forces act across regions with a strong directional selection. These findings underscore the need to ascertain the genetic background among races and to recognize meaningful within-race differentiation. Conservation actions should reflect this structure, promoting targeted seed exchange to counteract genetic erosion while respecting farmer preferences. Olotillo exemplifies how maize diversity is structured not only by genetics, but by cultural and management systems that shape evolution in situ.

genetics↗

bioRxiv2023

Isolation by environment is more important than isolation by distance along a tropical gradient in direct developing frogs

Abiotic factors are important for defining population structure and limiting gene flow, especially in ectotherm species, the challenge is to identify which ones are the most important and can produce a pattern of isolation by environment. Our study aim is to quantify the extent to which divergence is driven by abiotic factors such as temperature, precipitation and elevation. To do so, we used a direct-developing frog species, Craugastor loki that occurs along a steep elevation gradient. Using restriction-site associated DNA sequencing (RADseq) from individuals collected from 100 m to 2250 m of elevation at 13 localities at Sierra Madre de Chiapas in southern Mexico we described population structure using a variety of model-based clustering and landscape genomics approaches. We found that populations sampled at higher elevation correspond probably to an undescribed new species of Craugastor, and that populations from Craugastor loki between 120 m and 1500 m are clustered in two different genetic groups: a Pacific slope group and a Central Depression slope group. We found signatures of isolation by environment more important that isolation by distance in contributing to genetic divergence in this group of frogs at a fine scale. The environmental variables such as: mean temperature of wettest and warmest quarter, annual mean temperature, and seasonality in temperature and precipitation play an important role on population differentiation. Our results underscore the importance of abiotic factors as drivers and highlight the use of different approaches to illuminate fine scale population divergence given the complexity of disentangling the contribution of both patterns of isolation.

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↗