DNA methylation is the most studied epigenetic trait. It is considered a key factor in regulating plant development and physiology, and has been associated with the regulation of several genomic features, including transposon silencing, regulation of gene expression, and recombination rates. Nonetheless, understanding the relation between DNA methylation and recombination rates remains a challenge. This work explores the association between recombination rates and DNA methylation for two commercial rice varieties. The results show negative correlations between recombination rates and methylated cytosine counts for all contexts tested at the same time, and for CG and CHG contexts independently. In contrast, a positive correlation between recombination rates and methylated cytosine count is reported in CHH contexts. Similar behavior is observed when considering only methylated cytosines within genes, transposons, and retrotransposons. Moreover, it is shown that the centromere region strongly affects the relationship between recombination rates and methylation. Finally, machine learning regression models are applied to predict recombination using the count of methylated cytosines in the CHH context as the entrance feature. These findings shed light on the understanding of the recombination landscape of rice and represent a reference framework for future studies in rice breeding, genetics, and epigenetics.

Knowing how chromosome recombination works is essential for plant breeding. It enables the design of crosses between different varieties to combine desirable traits and create new ones. This is because the meiotic crossovers between homologous chromatids are not purely random, and various strategies have been developed to describe and predict such exchange events. Recent studies have used methylation data to predict chromosomal recombination in rice using machine learning models. This approach proved successful due to the presence of a positive correlation between the CHH context cytosine methylation and recombination rates in rice chromosomes. This paper assesses the question if methylation can be used to predict recombination in four plant species: Arabidopsis, maize, sorghum, and tomato. The results indicate a positive association between CHH context methylation and recombination rates in certain plant species, with varying degrees of strength in their relationships. The CG and CHG methylation contexts show negative correlation with recombination. Methylation data was key effectively in predicting recombination in sorghum and tomato, with a mean determination coefficient of 0.65 ± 0.11 and 0.76 ± 0.05, respectively. In addition, the mean correlation values between predicted and experimental recombination rates were 0.83 ± 0.06 for sorghum and 0.90 ± 0.05 for tomato, confirming the significance of methylomes in both monocotyledonous and dicotyledonous species. The predictions for Arabidopsis and maize were not as accurate, likely due to the comparatively weaker relationships between methylation contexts and recombination, in contrast to sorghum and tomato, where stronger associations were observed. To enhance the accuracy of predictions, further evaluations using data sets closely related to each other might prove beneficial. In general, this methylome-based method holds great potential as a reliable strategy for predicting recombination rates in various plant species, offering valuable insights to breeders in their quest to develop novel and improved varieties.

Domestic pigeons have high polymorphism in plumage morphs and colours. The genes that affect colour and coat patterns can be used to estimate genetic profiles that allow us to deduce the structures of populations, establish whether they are in a population equilibrium and learn the genetic similarity among them. This article tested these population components and the existing relationships among cities in northern South America, Western Europe and Singapore (Southeast Asia) through the inventory of phenotypic frequencies and the estimation of allele frequencies for the Pattern, Grizzle, Background colour, Spread, Crest, Recessive white and Feathered feet loci. The Hardy–Weinberg equilibrium was evaluated based on the Pattern and Grizzle loci. The results showed a higher genetic diversity in populations from northern South America with respect to the one from Western Europe, although the differentiation among cities was low ( G _ST = 0.0759). Several populations were not in the Hardy–Weinberg equilibrium for the evaluated loci, and a significant correlation between genetic and geographic distances was not found. The relatively small home range of the pigeons and the dispersion carried out by humans are discussed as possible explanations for the current genetic profiles.

Meiotic recombination is a crucial cellular process, being one of the major drivers of evolution and adaptation of species. In plant breeding, crossing is used to introduce genetic variation among individuals and populations. While different approaches to predict recombination rates for different species have been developed, they fail to estimate the outcome of crossings between two specific accessions. This paper builds on the hypothesis that chromosomal recombination correlates positively to a measure of sequence identity. It presents a model that uses sequence identity, combined with other features derived from a genome alignment (including the number of variants, inversions, absent bases, and CentO sequences) to predict local chromosomal recombination in rice. Model performance is validated in an inter-subspecific indica x japonica cross, using 212 recombinant inbred lines. Across chromosomes, an average correlation of about 0.8 between experimental and prediction rates is achieved. The proposed model, a characterization of the variation of the recombination rates along the chromosomes, can enable breeding programs to increase the chances of creating novel allele combinations and, more generally, to introduce new varieties with a collection of desirable traits. It can be part of a modern panel of tools that breeders can use to reduce costs and execution times of crossing experiments.

La proporción entre el segundo y cuarto dígito (2D/4D) ha sido bien estudiada como un dimorfismo sexual que puede resultar de los efectos androgénicos prenatales sobre la expresión de los genes homeobox. Se ha encontrado que este dimorfismo exhibe patrones filogenéticos en el cual las hembras tienen mayor proporción entre dígitos en especies mamíferas y menor proporción entre dígitos en especies de aves y reptiles. Este estudio midió los dígitos segundo y cuarto de todos las extremidades, en 25 especímenes machos y 25 especímenes hembras adultos de Gonatodes albogularis. Se determinó que no existían diferencias significativas entre la proporción (2D/4D) en machos y hembras como dimorfismo sexual de la especie. Estos resultados indican que esta especie de lagartija arbórea se desvía de la proporción entre dígitos mostrada por especies diápsida. Posibles factores ambientales asociados son discutidos.