Many endemic species present disjunct geographical distribution; therefore, they are suitable models to test hypotheses about the ecological and evolutionary mechanisms involved in the origin of disjunct distributions in these habitats. We studied the genetic structure and phylogeography of Tibouchina papyrus (Melastomataceae), endemic to rocky savannas in Central Brazil, to test hypothesis of vicariance and dispersal in the origin of the disjunct geographical distribution. We sampled 474 individuals from the three localities where the species is reported: Serra dos Pirineus, Serra Dourada, and Serra de Natividade. Analyses were based on the polymorphisms at cpDNA and on nuclear microsatellite loci. To test for vicariance and dispersal we constructed a median-joining network and performed an analysis of molecular variance (AMOVA). We also tested population bottleneck and estimated demographic parameters and time to most recent common ancestor (TMRCA) using coalescent analyses. A remarkable differentiation among populations was found. No significant effect of population expansion was detected and coalescent analyses showed a negligible gene flow among populations and an ancient coalescence time for chloroplast genome. Our results support that the disjunct distribution of T. papyrus may represent a climatic relict. With an estimated TMRCA dated from ∼836.491 ± 107.515 kyr BP (before present), we hypothesized that the disjunct distribution may be the outcome of bidirectional expansion of the geographical distribution favored by the drier and colder conditions that prevailed in much of Brazil during the Pre-Illinoian glaciation, followed by the retraction as the climate became warmer and moister.

ABSTRACT. Geographical genetics allows the evaluation of evolutionary processes underlying genetic variation within and among local populations and forms the basis for establishing more effective strategies for biodiversity conservation at the population level. In this study, we used explicit spatial analyses to investigate molecular genetic variation (estimated using 7 microsatellite markers) of Pseudoplatystoma punctifer, by using samples obtained from 15 localities along the Madeira River and Solimões, Amazon Basin. A high genetic diversity was observed associated with a relatively low F ST (0.057; P < 0.001), but pairwise F ST values ranged from zero up to 0.21 when some pairs of populations were compared. These F ST values Geographical genetics of Pseudoplatystoma punctifer have a relatively low correlation with geographic distances (r = 0.343; P = 0.074 by Mantel test), but a Mantel correlogram revealed that close populations (up to 80 km) tended to be more similar than expected by chance (r = 0.360; P = 0.015). The correlogram also showed a exponential-like decrease of genetic similarity with distance, with a patch-size of around 200 km, compatible with isolation-by-distance and analogous processes related to local constraints of dispersal and spatially structured levels of gene flow. The pattern revealed herein has important implications for establishing strategies to maintain genetic diversity in the species, especially considering the threats due to human impacts caused by building large dams in this river system.

Species Cichla piquiti and Cichla kelberi are found in the Serra da Mesa reservoir, Goiás and are sedentary with diurnal habits. This study aimed to evaluate the magnitude and distribution of genetic variability in subpopulations of C. piquiti with specific microsatellite loci and to test transferability in other microsatellite markers for C. kelberi. We analyzed 99 individuals of C. piquiti from seven points to evaluate genetic diversity and structure with 10 microsatellite loci. Transferability of 75 loci was tested in C. kelberi to increase microsatellite markers available. Genetic structure was assessed with Bayesian clustering. Global FST for C. piquiti was weak (0.056), but FIS (0.598) and FIT (0.621) were significantly high, indicating that the mating system has a strong influence on the organization of genetic variability with most mating among related. Two genetic groups were evidenced with most individuals allocated to a single group. Transferability of microsatellite loci for C. kelberi had low polymorphism. The level of genetic diversity was low, increasing inbreeding and suggesting that few individuals of C. piquiti colonized the reservoir during its installation due founder effect. Other factors as reproductive behavior and overfishing can act to decrease genetic diversity. Therefore, we reinforce the need for genetic monitoring to avoid loss of genetic diversity that can be intensified both construction of hydropower plants and ecological and reproductive aspects in some fish species.

The SARS-CoV-2 pandemic has demonstrated the need for genomic epidemiology surveillance. To date, various methodologies have been applied, including metagenomic ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 21 (1): gmr19018C.P. Targueta et al. 2 approaches and amplicon-based sequencing associated with highthroughput sequencing platforms. We adapted some details in amplicon-based sequencing using a SARS-CoV-2 community panel (Illumina AmpliSeq), with additional modifications for balanced and high-quality sequencing using the MiSeq platform. The modified protocol was used to detect circulating SARS-CoV-2 variants in Goiás state, Brazil. Initially, RNA samples were obtained from swab samples from 15 patients from the state of Goiás, Brazil, in November/2020 and February/2021 to validate protocol steps. The libraries were prepared following AmpliSeq for Illumina workflow with modifications; subsequently, we analyzed 305 positive samples collected from the state of Goiás from December 2020 to July 2021. For protocol improvement, we removed the need to treat samples with DNAse and demonstrated the importance of quantification by qPCR before and after library dilution. No fragmentation pattern was observed in the samples analyzed with Bioanalyzer. The libraries returned sequencing results that were used for genome assembly and variant detection. We were able to assemble SARS-CoV-2 genomes from 318 samples, which were used to identify 13 variants of coronavirus circulating in Goiás throughout those months. Variants of concern, such as Alpha (B.1.1.7), Gamma (P.1) and Delta (B.1.617.2) were detected; the latter was detected at first in Goiás in April 2021. The modifications in the workflow we developed were successfully applied to detect SARS-CoV-2 variants, resulting in high coverage genome assembly, and they can be used to increase the number of genome sequences and aid in epidemiological surveillance in Brazil.