Genetica

The high dynamism of repetitive DNAs is a major driver of chromosome evolution. In particular, the accumulation of repetitive DNA sequences has been reported as part of the differentiation of sex-specific chromosomes. In turn, the fish species of the genus Megaleporinus are a monophyletic clade in which the presence of differentiated ZZ/ZW sex chromosomes represents a synapomorphic condition, thus serving as a suitable model to evaluate the dynamic evolution of repetitive DNA classes. Therefore, transposable elements (TEs) and in tandem repeats were isolated and located on chromosomes of Megaleporinus obtusidens and M...

Chamaecrista is a Pantropical legume genus of the tribe Cassieae, which includes six other genera. In contrast to most of the other Cassieae genera, Chamaecrista shows significant variability in chromosome number (from 2n = 14 to 2n = 56), with small and morphologically similar chromosomes. Here, we performed a new cytomolecular analysis on chromosome number, genome size, and rDNA site distribution in a molecular phylogenetic perspective to interpret the karyotype trends of Chamaecrista and other two genera of Cassieae, seeking to understand their systematics and evolution...

Reproduction of water frog hybrids Pelophylax esculentus (Pelophylax ridibundus x Pelophylax lessonae) is associated with hemiclonal reproduction and backcrossing. The hemiclonal mode of reproduction occurs within P. esculentus allodiploids. In this case, the unrecombined genome of one parental species is transmitted to the offspring after premeiotic elimination of the chromosome set of the second parental species. Usually, the chromosome set of P. lessonae is eliminated, and the altered genome of P. ridibundus is passed on to the progeny...

Satellite DNAs (satDNAs) are highly repetitive sequences that occur in virtually all eukaryotic genomes and can undergo rapid copy number and nucleotide sequence variation among relatives. After chromosomal mapping of the satDNA JcSAT1, it was found a large accumulation at subtelomeres of Jatropha curcas (subgenus Curcas), but an absence of these monomers in J. integerrima (subgenus Jatropha). This fact suggests a dynamic scenario for this satellite repeat in Jatropha genomes. Here, we used a multitasking approach (sequence analysis, DNA blotting and chromosomal mapping) to investigate the molecular organization and chromosomal abundance and distribution of JcSAT1 in a broader group of species from the subgenus Jatropha (J...

Dehydration is a stress factor for organisms inhabiting natural habitats where water is scarce. Thus, it may be expected that species facing arid environments will develop mechanisms that maximize resistance to desiccation. Insects are excellent models for studying the effects of dehydration as well as the mechanisms and processes that prevent water loss since the effect of desiccation is greater due to the higher area/volume ratio than larger animals. Even though physiological and behavioral mechanisms to cope with desiccation are being understood, the genetic basis underlying the mechanisms related to variation in desiccation resistance and the context-dependent effect remain unsolved...

The African grass or Nile rat (NR) (Arvicanthis niloticus) is a herbivorous diurnal rodent which is used as a biological model for research on type 2 diabetes mellitus (T2DM) and the circadian rhythm. Similar to humans, male NRs develop T2DM with high-carbohydrate diets. The NR thus provides a unique opportunity to identify the nutritional and underlying genetic factors that characterise human T2DM, as well as the effects of potential anti-diabetic phytochemicals such as Water-Soluble Palm Fruit Extract. Whole genome sequencing (WGS) could help identify possible genetic causes why NRs spontaneously develop T2DM in captivity...

The fluctuation experiment, devised by Luria and Delbrück in 1943, remains the method of choice for measuring microbial mutation rates in the laboratory. While most inference problems commonly encountered in a fluctuation experiment can be tackled by existing standard algorithms, investigators from time to time run into nonstandard problems not amenable to any existing algorithms. A major obstacle to solving these nonstandard problems is the construction of confidence intervals for mutation rates. This note describes methods for two important categories of nonstandard problems, namely, pooling data from separate experiments and analyzing grouped mutant count data, focusing on the construction of likelihood ratio confidence intervals...

There has been a continuous interest in understanding the patterns of genetic diversity in natural populations because of the role of intraspecific genetic diversity as the basis of all evolutionary change and thus, its potential effects on population persistence when facing environmental changes. Here, we provided the first description of genetic diversity distribution and population structure of Anacardium occidentale L. (cashew) from the Brazilian Cerrado, one of the most economically important tropical crops in the world...

The light-dark cycle significantly impacts the growth and development of animals. Mantis shrimps (Oratosquilla oratoria) receive light through their complex photoreceptors. To reveal the adaptive expression mechanism of the mantis shrimp induced in a dark environment, we performed comparative transcriptome analysis with O. oratoria cultured in a light environment (Oo-L) as the control group and O. oratoria cultured in a dark environment (Oo-D) as the experimental group. In the screening of differentially expressed genes (DEGs) between the Oo-L and Oo-D groups, a total of 88 DEGs with |log2FC| > 1 and FDR < 0...

The Drosophila GAGA-factor encoded by the Trithorax-like (Trl) gene is DNA-binding protein with unusually wide range of applications in diverse cell contexts. In Drosophila spermatogenesis, reduced GAGA expression caused by Trl mutations induces mass autophagy leading to germ cell death. In this work, we investigated the contribution of mitochondrial abnormalities to autophagic germ cell death in Trl gene mutants. Using a cytological approach, in combination with an analysis of high-throughput RNA sequencing (RNA-seq) data, we demonstrated that the GAGA deficiency led to considerable defects in mitochondrial ultrastructure, by causing misregulation of GAGA target genes encoding essential components of mitochondrial molecular machinery...

Identifying homologs is an important process in the analysis of genetic patterns underlying traits and evolutionary relationships among species. Analysis of gene families is often used to form and support hypotheses on genetic patterns such as gene presence, absence, or functional divergence which underlie traits examined in functional studies. These analyses often require precise identification of all members in a targeted gene family. Manual pipelines where homology search and orthology assignment tools are used separately are the most common approach for identifying small gene families where accurate identification of all members is important...

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This paper describes the preparation of flow-sorted chromosome paints from the Iberian Rock lizard Iberolacerta monticola, exemplifying their subsequent use in cross-species comparisons of chromosome painting. We carried out comparative analyses of chromosome evolution in the congeneric species I. galani and I. bonnali, as well as in two other species of Lacertini (Lacerta schreiberi and Timon lepidus) whose sex chromosomes were also studied through comparative genomic hybridization. Most species of Lacertini possess a diplod number of 2n = 38, with 36 acrocentric macrochromosomes and 2 microchromosomes...

Ionotropic glutamate receptors are ligand-gated nonselective cation channels that mediate neurotransmission in the central nervous system of animals. Plants possess homologous proteins called glutamate receptor-like channels (GLRs) which are involved in vital physiological processes including seed germination, long-distance signaling, chemotaxis, Ca2+ signaling etc. Till now, a comprehensive genome-wide analysis of the GLR gene family members in different economically important species of Brassica is missing...

The scarlet macaw, Ara macao, is a neotropical parrot that contains two described subspecies with broadly discrete geographical distributions. One subspecies, A. m. macao, is found from South America north into southwestern Costa Rica, while the second subspecies, A. m. cyanoptera, is found from eastern Costa Rica north into central Mexico. Our previous research using mitochondrial data to examine phylogeographical divergence across the collective range of these two subspecies concluded that they represent distinct evolutionary entities, with minimal contemporary hybridization between them...

In the Neotropical region, one of the most diverse families of freshwater fishes is the monophyletic Serrasalmidae. Karyotypically, the family shows high diversity in chromosome numbers (2n = 54 to 64). However, little is discussed about whether the chromosomal changes are associated with cladogenetic events within this family. In the present study, we evaluated the role of chromosomal changes in the evolutionary diversification of Serrasalmidae. Our phylogenetic sampling included 36 species and revealed three main clades...

The sterile insect technique (SIT) is a highly effective biologically-based method for the population suppression of highly invasive insect pests of medical and agricultural importance. The efficacy of SIT could be significantly enhanced, however, by improved methods of male sterilization that avoid the fitness costs of irradiation. An alternative sterilization method is possible by gene-editing that targets genes essential for sperm maturation and motility, rendering them nonfunctional, similar to the CRISPR-Cas9 targeting of β2-tubulin in the genetic model system, Drosophila melanogaster...

AP2/ERF (APETALA2/Ethylene Response Factor) is a family of transcription factors that play essential roles in regulating gene expression in response to various environmental stimuli, including biotic and abiotic stresses, hormone signaling, and developmental processes. Pisum sativum (L.), commonly known as garden pea, is a winter crop sensitive to high temperatures and can also be affected by extreme cold and drought conditions. This study performed a genome-wide analysis of AP2/ERF genes and identified 153 AP2/ERF genes in P...

In addition to their roles in developmental and metabolic processes, MYB transcription factors play crucial roles in plant defense mechanisms and stress responses. A comprehensive analysis of six pearl millet genomes revealed the presence of 1133 MYB genes, which can be classified into four phylogenetically distinct subgroups. The duplication pattern of MYB genes across the pearl millet genomes demonstrates their conserved and similar evolutionary history. Overall, MYB genes were observed to be involved in drought and heat stress responses, with stronger differential expressed observed in root tissues...

Adaptation to various altitudes and oxygen levels is a major aspect of vertebrate evolution. Hemoglobin is an erythrocyte protein belonging to the globin superfamily, and the α-, β-globin genes of jawed vertebrates encode tetrameric ((α2 β2 ) hemoglobin, which contributes to aerobic metabolism by delivering oxygen from the respiratory exchange surfaces into cells. However, there are various gaps in knowledge regarding hemoglobin gene evolution, including patterns in cartilaginous fish and the roles of gene conversion in various taxa...