Abstract：
:Two catalytic functions were required, minimally, for the appearance of DNA in evolution: a ribonucleotide reductase (RNR) and a reverse transcriptase (RT). If one accepts the explanatory strength of the RNA world model, it is clear that DNA molecules arose in the RNA world at some stage during the early evolution of cells. I suggest that competition for limited and valuable resources such as nucleotides, amino acids, and sugars made an early appearance among RNA cells, RNA viruses, viroids, and RNA plasmids. Structural and functional similarities between the different types of polymerases favor the simple hypothesis that the first RTs were RNA polymerase mutants that preferentially joined together preexisting deoxyribonucleotide triphosphates (dNTPs) using RNA templates. What was the role of dNTPs inside cells before DNA was synthesized and tested by natural selection? The oxygen atom that is removed by the reductase is of crucial importance to many ribozyme functions, since the 2'-OH is a strong nucleophile that forms transitional states during catalysis. Consequently, a RNR may have been used by cellular parasites to inhibit ribozyme action. Thus, DNA may have been, initially, an inert by-product of retrotranscription in lineages that acquired RTs and could synthesize DNA molecules using cellular RNA templates to detoxify the intracellular environment. DNA was useless as template until a transcriptase (DNA-dependent RNA polymerase) evolved that could copy (-)DNA to reconstitute the (+)RNA genome, indeed a successful way of confronting ribonuclease threats in the RNA world.
journal_name
J Mol Evoljournal_title
Journal of molecular evolutionauthors
León PEdoi
10.1007/pl00006368subject
Has Abstractpub_date
1998-08-01 00:00:00pages
122-6issue
2eissn
0022-2844issn
1432-1432journal_volume
47pub_type
杂志文章abstract：:We have continued our program aimed at understanding the origin and evolution of the genetic code and the process of protein synthesis by comparing the rates of esterification of 5'-AMP by a series of hydrophobic N-acetylamino acids. The reaction clearly shows differences in reaction rate (AcPhe greater than AcLeu gre...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/BF02101000
更新日期：1986-01-01 00:00:00
abstract：:The mutation and selection of regulatory DNA sequences are presented as an ideal model system of molecular evolution where genotype, phenotype, and fitness can be explicitly and independently characterized. In this theoretical study, we construct an explicit model for the evolution of regulatory sequences, making use ...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/s00239-002-2335-z
更新日期：2002-10-01 00:00:00
abstract：:The semen of many primate species coagulates into a mating plug believed to prevent the sperm of subsequent mating events from accessing the ova. The texture of the coagulum varies among species: from a semisoft mass in humans to a firm plug in chimpanzees. In humans, a component of the coagulum, semenogelin I, also i...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/s00239-002-2463-0
更新日期：2003-08-01 00:00:00
abstract：:This study examines the diverse maximum wavelength absorption (lambdamax) found in crayfishes (Decapoda: Cambaridae and Parastacidae) and the associated genetic variation in their opsin locus. We measured the wavelength absorption in the photoreceptors of six species that inhabit environments of different light intens...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/pl00006257
更新日期：1997-11-01 00:00:00
abstract：:The RpoS sigma factor in proteobacteria regulates genes in stationary phase and in response to stress. Although of conserved function, the RpoS regulon may have different gene composition across species due to high genomic diversity and to known environmental conditions that select for RpoS mutants. In this study, the...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/s00239-010-9352-0
更新日期：2010-06-01 00:00:00
abstract：:There has been considerable discussion in recent years on the evolution of the tandemly repeated multigene families, since some organisms show a concerted model whereas others show a birth-and-death model. This controversial subject extends to several species of fish. In this study, three species of the Sparidae famil...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/s00239-013-9541-8
更新日期：2013-03-01 00:00:00
abstract：:An exhaustive computer-assisted analysis of the Moloney murine leukemia virus nucleotide sequence shows numerous deviations in the oligomeric distribution, suggesting three overlapping levels of a stepwise duplicative evolution. (1) The sequence fits the universal rule of TG/CT excess which has been proposed as the co...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/BF00171820
更新日期：1992-11-01 00:00:00
abstract：:The codon assignment of the quasi-universal genetic code can be assumed to have resulted from the evolutionary pressures that prevailed when the code was still evolving. Here, we review studies of the structure of the genetic code based on optimization models. We also review studies that, from the structure of the cod...
journal_title：Journal of molecular evolution
pub_type： 杂志文章,评审
doi：10.1007/s00239-009-9287-5
更新日期：2009-11-01 00:00:00
abstract：:In the plant chloroplast genome the codon usage of the highly expressed psbA gene is unique and is adapted to the tRNA population, probably due to selection for translation efficiency. In this study the role of selection on codon usage in each of the fully sequenced chloroplast genomes, in addition to Chlamydomonas re...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/pl00006325
更新日期：1998-04-01 00:00:00
abstract：:Explicit evaluation of the accuracy and power of maximum likelihood and Bayesian methods for detecting site-specific positive Darwinian selection presents a challenge because selective consequences of single amino acid changes are generally unknown. We exploited extensive molecular and functional characterization of a...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/s00239-008-9172-7
更新日期：2008-11-01 00:00:00
abstract：:As the origin(s) of life on Earth remains an open question, detailed characteristics about the "last universal ancestor" (LUA) continue to be obscured. Here we provide arguments that strengthen the bacterial-like nature of the LUA. Our view attempts to recreate the evolution of archaeal lipids, the major components of...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/s00239-006-0141-8
更新日期：2007-03-01 00:00:00
abstract：:Small heat shock proteins (sHSPs), as one subclass of molecular chaperones, are important for cells to protect proteins under stress conditions. Unlike the large HSPs (represented by Hsp60 and Hsp70), sHSPs are highly divergent in both primary sequences and oligomeric status, with their evolutionary relationships bein...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/s00239-005-0076-5
更新日期：2006-03-01 00:00:00
abstract：:Molluscan shells are composed of calcium carbonates, with small amounts of extracellular matrices secreted from mantle epithelial cells. Many types of shell matrix proteins (SMPs) have been identified from molluscan shells or mantle cells. The pen shell Atrina pectinata (Pinnidae) has two different shell microstructur...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/s00239-020-09977-7
更新日期：2020-12-01 00:00:00
abstract：:Exon-shuffling is an important mechanism accounting for the origin of many new proteins in eukaryotes. However, its role in the creation of proteins in the ancestor of prokaryotes and eukaryotes is still debatable. Excess of symmetric exons is thought to represent evidence for exon-shuffling since the exchange of exon...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/s00239-004-0318-y
更新日期：2005-09-01 00:00:00
abstract：:A cDNA encoding a new member of the gene family of major royal jelly proteins (MRJPs) from the honeybee, Apis mellifera, was isolated and sequenced. Royal jelly (RJ) is a secretion of the cephalic glands of nurse bees. The origin and biological function of the protein component (12.5%, w/w) of RJ is unknown. We show t...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/pl00006551
更新日期：1999-08-01 00:00:00
abstract：:Sequence comparisons of 14 distinct MHC class I cDNA clones isolated from species representing the three major taxonomic lineages of Felidae (domestic cat lineage, ocelot lineage, and pantherine lineage) revealed that feline MHC class I alleles have highly mosaic structures with short polymorphic sequence motifs that ...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/BF00178246
更新日期：1994-07-01 00:00:00
abstract：:Liverworts are well supported as the sister group to all other land plants (embryophytes) by molecular data. Observations strongly supporting this earliest dichotomy in embryophyte evolution are the strikingly different introns occurring in the mitochondrial DNAs of liverworts versus non-liverwort embryophytes (NLE), ...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/s00239-010-9348-9
更新日期：2010-05-01 00:00:00
abstract：:The slow-evolving mitochondrial DNAs of plants have potentially conserved information on the phylogenetic branching of the earliest land plants. We present the nad2 gene structures in hornworts and liverworts and in the presumptive earliest-branching vascular land plant clade, the Lycopodiopsida. Taken together with t...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/s00239-002-2324-2
更新日期：2002-09-01 00:00:00
abstract：:We constructed a cDNA library for the beetle, Tribolium castaneum. This library was screened using a cloned amylase gene from Drosophila melanogaster as a molecular probe. Beetle amylase cDNA clones were isolated from this bank, and the nucleotide sequence was obtained for a cDNA clone with a coding capacity for 228 a...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/BF02099856
更新日期：1987-01-01 00:00:00
abstract：:The evolution of ligand specificity underlies many important problems in biology, from the appearance of drug resistant pathogens to the re-engineering of substrate specificity in enzymes. In studying biomolecules, however, the contributions of macromolecular sequence to binding specificity can be obscured by other se...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/s00239-003-2481-y
更新日期：2003-09-01 00:00:00
abstract：:Studies during the last 20 years have shown that the chromosomes of many organisms, especially those of higher vertebrates, consist of a series of segments having different properties. These can be recognized as, for example, G- and R-bands. Recent studies have indicated that genes tend to lie in the R-bands rather th...
journal_title：Journal of molecular evolution
pub_type： 杂志文章,评审
doi：10.1007/BF02407346
更新日期：1993-08-01 00:00:00
abstract：:Heterokonts are evolutionarily important as the most nutritionally diverse eukaryote supergroup and the most species-rich branch of the eukaryotic kingdom Chromista. Ancestrally photosynthetic/phagotrophic algae (mixotrophs), they include several ecologically important purely heterotrophic lineages, all grossly unders...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/s00239-004-0353-8
更新日期：2006-04-01 00:00:00
abstract：:Mitochondrial small-subunit (19S) rDNA sequences were obtained from 10 angiosperms to further characterize sequence divergence levels and structural variation in this molecule. These sequences were derived from seven holoparasitic (nonphotosynthetic) angiosperms as well as three photosynthetic plants. 19S rRNA is comp...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/pl00006267
更新日期：1997-12-01 00:00:00
abstract：:Alu elements are not distributed homogeneously throughout the human genome: old elements are preferentially found in the GC-rich parts of the genome, while young Alus are more often found in the GC-poor parts of the genome. The process giving rise to this differential distribution remains poorly understood. Here we in...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/s00239-004-0020-0
更新日期：2005-03-01 00:00:00
abstract：:Natural populations of the Midas cichlid species in several different crater lakes in Nicaragua exhibit a conspicuous color polymorphism. Most individuals are dark and the remaining have a gold coloration. The color morphs mate assortatively and sympatric population differentiation has been shown based on neutral mole...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/s00239-010-9340-4
更新日期：2010-05-01 00:00:00
abstract：:The best reconstructions of the history of life will use both molecular time estimates and fossil data. Errors in molecular rate estimation typically are unaccounted for and no attempts have been made to quantify this uncertainty comprehensively. Here, focus is primarily on fossil calibration error because this error ...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/s00239-004-2624-9
更新日期：2004-08-01 00:00:00
abstract：:The symbiotic protists of the lower termite have been regarded as a model of early-branched eukaryotes because of their simple cellular systems and morphological features. However, cultivation of these symbiotic protists is very difficult. For this reason, these interesting protists have not been well characterized in...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/s002390010129
更新日期：2001-01-01 00:00:00
abstract：:The trnT-trnF region is located in the large single-copy region of the chloroplast genome. It consists of the trnL intron, a group I intron, and the trnT-trnL and trnL-trnF intergenic spacers. We analyzed the evolution of the region in the three genera of the gymnosperm lineage Gnetales (Gnetum, Welwitschia, and Ephed...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/s00239-004-0240-3
更新日期：2005-10-01 00:00:00
abstract：:Here we analyze the molecular evolution of the beta-esterase gene cluster in the Drosophila genus using the recently released genome sequences of 12 Drosophila species. Molecular evolution in this small cluster is noteworthy because it contains contrasting examples of the types and stages of loss of gene function. Spe...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/s00239-009-9236-3
更新日期：2009-07-01 00:00:00
abstract：:Previous studies have shown that pituitary growth hormone displays an episodic pattern of evolution, with a slow underlying evolutionary rate and occasional sustained bursts of rapid change. The present study establishes that pituitary prolactin shows a similar pattern. During much of tetrapod evolution the sequence o...
journal_title：Journal of molecular evolution
pub_type： 杂志文章
doi：10.1007/s002390010049
更新日期：2000-05-01 00:00:00
