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Journal of Molecular Evolution

Omar Navarro Leija, Sanju Varghese, Mira V Han
Evolutionary constraint for insertions and deletions (indels) is not necessarily equal to constraint for nucleotide substitutions for any given region of a genome. Knowing the variation in indel-specific evolutionary rates across the sequence will aid our understanding of evolutionary constraints on indels, and help us infer how indels have contributed to the evolution of the sequence. However, unlike for nucleotide substitutions, there has been no phylogenetic method that can statistically infer significantly different rates of indels across the sequence space independent of substitution rates...
October 21, 2016: Journal of Molecular Evolution
Rosa Calvello, Maria A Panaro, Rosaria Salvatore, Vincenzo Mitolo, Antonia Cianciulli
The "canonical" introns begin by the dinucleotide GT and end by the dinucleotide AG. GT, together with a few downstream nucleotides, and AG, with a few of the immediately preceding nucleotides, are thought to be the strongest splicing signals (5'ss and 3'ss, respectively). We examined the composition of the intronic initial and terminal hexanucleotides of the mitochondrial solute carrier genes (SLC25A's) of zebrafish, chicken, mouse, and human. These genes are orthologous and we selected the transcripts in which the arrangement of exons and introns was superimposable in the species considered...
October 20, 2016: Journal of Molecular Evolution
M J Madison-Villar, Cheng Sun, Nelson C Lau, Matthew L Settles, Rachel Lockridge Mueller
Most of the largest vertebrate genomes are found in salamanders, a clade of amphibians that includes 686 species. Salamander genomes range in size from 14 to 120 Gb, reflecting the accumulation of large numbers of transposable element (TE) sequences from all three TE classes. Although DNA loss rates are slow in salamanders relative to other vertebrates, high levels of TE insertion are also likely required to explain such high TE loads. Across the Tree of Life, novel TE insertions are suppressed by several pathways involving small RNA molecules...
October 14, 2016: Journal of Molecular Evolution
Massimo Di Giulio
The coevolution theory of the origin of the genetic code maintains that the biosynthetic relationships between amino acids co-evolved with the genetic code organization. In other words, the metabolism of amino acids co-evolved with the organization of the genetic code because the biosynthetic pathways of amino acids occurred on tRNA-like molecules. Thus, a heterotrophic origin of amino acids-also only of those involved in the early phase of the structuring of the genetic code-would seem to contradict the main postulate of the coevolution theory...
October 14, 2016: Journal of Molecular Evolution
Matthew J Jenny, Samantha L Payton, David A Baltzegar, Jeffrey D Lozier
Mechanisms by which organisms genetically adapt to environmental conditions are of fundamental importance to studies of evolutionary biology and environmental physiology. Natural selection acts on existing genetic variation leading to adaptation through selection of new mutations that confer beneficial advantages to populations. The American oyster, Crassostrea virginica, is an excellent model to investigate interactions between environmental and ecological factors as driving forces for natural selection. A great example of this is represented by the diversity of C...
September 27, 2016: Journal of Molecular Evolution
John M Braverman, Matthew B Hamilton, Brent A Johnson
There are marked variations among loci and among lineages in rates of nucleotide substitution. The generation time hypothesis (GTH) is a neutral explanation for substitution rate heterogeneity that has genomewide application, predicting that species with shorter generation times accumulate DNA sequence substitutions faster than species with longer generation times do since faster genome replication provides more opportunities for mutations to occur and reach fixation by genetic drift. Relatively few studies have rigorously evaluated the GTH in plants, and there are numerous alternative hypotheses for plant substitution rate variation...
September 3, 2016: Journal of Molecular Evolution
Michael Yarus
Given two primordial conditions that seem likely to be common, near-ideal reactions for evolutionary progress are realized. These requisites are sporadic availability of pooled reactants and evolutionarily useful products within a pool's repertoire. These intrinsically optimizing circumstances function without genetics, and therefore can help evolve a first genetic system. This process is termed chance utility.
September 1, 2016: Journal of Molecular Evolution
J Baz Jackson
The hypothesis that a natural pH gradient across inorganic membranes lying between the ocean and fluid issuing from hydrothermal alkali vents provided energy to drive chemical reactions during the origin of life has an attractive parallel with chemiosmotic ATP synthesis in present-day organisms. However, arguments raised in this review suggest that such natural pH gradients are unlikely to have played a part in life's origin. There is as yet no evidence for thin inorganic membranes holding sharp pH gradients in modern hydrothermal alkali vents at Lost City near the Mid-Atlantic Ridge...
August 2016: Journal of Molecular Evolution
Niccolo Caldararo
A number of recent articles have appeared on the Denisova fossil remains and attempts to produce DNA sequences from them. One of these recently appeared in Science by Vernot et al. (Science 352:235-239, 2016). We would like to advance an alternative interpretation of the data presented. One concerns the problem of contamination/degradation of the determined DNA sequenced. Just as the publication of the first Neandertal sequence included an interpretation that argued that Neandertals had not contributed any genes to modern humans, the Denisovan interpretation has considerable influence on ideas regarding human evolution...
August 2016: Journal of Molecular Evolution
Jae Young Choi, Charles F Aquadro
In Drosophila, many studies have examined the short- or long-term evolution occurring across synonymous sites. Few, however, have examined both the recent and long-term evolution to gain a complete view of this selection. Here we have analyzed Drosophila ananassae DNA polymorphism and divergence data using several different methods, and have identified evidence of positive selection favoring preferred codons in both recent and long-term evolutionary time scale. Further in D. ananassae, the strength of selection for preferred codons was stronger on the X chromosome compared to the autosomes...
August 2016: Journal of Molecular Evolution
Christiane Paul, Frank Kirschbaum, Victor Mamonekene, Ralph Tiedemann
Voltage-gated sodium channels, Nav1, play a crucial role in the generation and propagation of action potentials and substantially contribute to the shape of their rising phase. The electric organ discharge (EOD) of African weakly electric fish (Mormyroidea) is the sum of action potentials fired from all electrocytes of the electric organ at the same time and hence voltage-gated sodium channels are one factor-together with the electrocyte's morphology and innervation pattern-that determines the properties of these EODs...
August 2016: Journal of Molecular Evolution
Geoffrey S Diemer, Kenneth M Stedman
The Microviridae are increasingly becoming recognized as one of the most globally ubiquitous and highly diverse virus families, and as such, provide an advantageous model for studying virus evolution and adaptation. Here, we utilize microvirus sequences from diverse physiochemical environments, including novel sequences from a high-temperature acidic lake, to chart the outcome of natural selection in the main structural protein of the virus. Each icosahedral microvirus virion is composed of sixty identical capsid proteins that interact along twofold, threefold and fivefold symmetry axis interfaces to encapsidate a small, circular, single-stranded DNA genome...
August 2016: Journal of Molecular Evolution
Daniel J Gates, Susan R Strickler, Lukas A Mueller, Bradley J S C Olson, Stacey D Smith
MYB transcription factors play an important role in regulating key plant developmental processes involving defense, cell shape, pigmentation, and root formation. Within this gene family, sequences containing an R2R3 MYB domain are the most abundant type and exhibit a wide diversity of functions. In this study, we identify 559 R2R3 MYB genes using whole genome data from four species of Solanaceae and reconstruct their evolutionary relationships. We compare the Solanaceae R2R3 MYBs to the well-characterized Arabidopsis thaliana sequences to estimate functional diversity and to identify gains and losses of MYB clades in the Solanaceae...
August 2016: Journal of Molecular Evolution
Wessel van der Loo, Maria João Magalhaes, Ana Lemos de Matos, Joana Abrantes, Fumio Yamada, Pedro J Esteves
Studies of the process of pseudogenization have widened our understanding of adaptive evolutionary change. In Rabbit, an alteration at the second extra-cellular loop of the CCR5 chemokine receptor was found to be associated with the pseudogenization of one of its prime ligands, the chemokine CCL8. This relationship has raised questions about the existence of a causal link between both events, which would imply adaptive gene loss. This hypothesis is evaluated here by tracing back the history of the genetic modifications underlying the chemokine pseudogenization...
August 2016: Journal of Molecular Evolution
A B Shcherban, E Z Kochieva, E A Salina
Allopolyploidization induces a multiple processes of genomic reorganization, including the structurally functional diversification of the homoeologous genes. An example of such diversification is the appearance of the Lr34 gene on chromosome 7D of bread wheat T. aestivum (BAD), the gene conferring durable, race non-specific protection against three fungal pathogens. In this study, we focused on the variability of a functionally critical region between exons 10-12 of Lr34 among diploid progenitors of wheat genomes and their respective polyploids...
June 2016: Journal of Molecular Evolution
Ferenc Orosz
Apicomplexan parasites cause serious illnesses, including malaria, in humans and domestic animals. The presence of apicortins is predominantly characteristic of this phylum. All the apicomplexan species sequenced contain an apicortin which unites two conserved domains: DCX and partial p25alpha. This paper identifies novel apicortin orthologs in silico and corrects in several cases the erroneous sequences of hypothetical apicortin proteins of Cryptosporidium, Eimeria, and Theileria genera published in databases...
June 2016: Journal of Molecular Evolution
Miguel Angel Fuertes, José Ramón Rodrigo, Carlos Alonso
It has been previously suggested that both the coding and the associated non-coding sequences of some human-mouse orthologs could evolve as a single unit. This letter deals with the observation that between mouse and humans some orthologs change significantly their compositional features as an indication that the molecular evolution is a local process. Moreover, the data shown indicate that the coding and the intron sequences of these orthologs do not evolve independently but instead both undergo a concerted evolution, evolving as a single unit, from a compositional cluster in mouse to a different compositional cluster in human...
June 2016: Journal of Molecular Evolution
Antonio Emidio Fortunato, Paolo Sordino, Nikos Andreakis
SOUL homologs constitute a heme-binding protein superfamily putatively involved in heme and tetrapyrrole metabolisms associated with a number of physiological processes. Despite their omnipresence across the tree of life and the biochemical characterization of many SOUL members, their functional role and the evolutionary events leading to such remarkable protein repertoire still remain cryptic. To explore SOUL evolution, we apply a computational phylogenetic approach, including a relevant number of SOUL homologs, to identify paralog forms and reconstruct their genealogy across the tree of life and within species...
June 2016: Journal of Molecular Evolution
Mark K Gunnell, Richard A Robison, Byron J Adams
A fundamental tenet of evolution is that alleles that are under negative selection are often deleterious and confer no evolutionary advantage. Negatively selected alleles are removed from the gene pool and are eventually extinguished from the population. Conversely, alleles under positive selection do confer an evolutionary advantage and lead to an increase in the overall fitness of the organism. These alleles increase in frequency until they eventually become fixed in the population. Francisella tularensis is a zoonotic pathogen and a potential biothreat agent...
June 2016: Journal of Molecular Evolution
Yanzhu Ji, J Andrew DeWoody
Transposable elements (TEs) are nearly ubiquitous among eukaryotic genomes, but TE contents vary dramatically among phylogenetic lineages. Several mechanisms have been proposed as drivers of TE dynamics in genomes, including the fixation/loss of a particular TE insertion by selection or drift as well as structural changes in the genome due to mutation (e.g., recombination). In particular, recombination can have a significant and directional effect on the genomic TE landscape. For example, ectopic recombination removes internal regions of long terminal repeat retrotransposons (LTR-RTs) as well as one long terminal repeat (LTR), resulting in a solo LTR...
June 2016: Journal of Molecular Evolution
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