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PubMed2026

Comparative Genomics Reveals Convergent Evolution Between Avivorous Bats (Ia io and Nyctalus aviator).

Investigating the genetic basis of dietary specialization can provide insights into the evolution of niche breadth. In this study, we employed comparative genomics to investigate the adaptive mechanisms enabling two bat species (Nyctalus aviator and Ia io) to shift from insectivory to seasonal bird consumption (avivorous bats). Our findings revealed adaptation related to immune response and lipid metabolism in avivorous bat species. Avivorous bats exhibit strong positive selection and convergent evolution in immune-related genes, which are under heightened selective pressure compared to those of non-avivorous bats. These species also display significantly fewer endogenous retroviral elements. These findings emphasized the significance of immune-driven adaptive evolution in avivory. Additionally, our results showed that the dietary evolution of avivorous bats is accompanied by convergent evolution associated with the lipid metabolism. Notably, CEPT1, the upstream gene required for the activation of the PPAR pathway, underwent positive selection and convergence, which may have affected lipid metabolism. These adaptations may enable avivorous bat species to face the challenge of immune response and nutrition during dietary niche expansion. These findings not only provide comprehensive insights into the adaptive evolution driving the unique diet of avivorous bats but also offered novel perspectives on the molecular mechanisms underlying ecological niche evolution in a dietary context.

Animals↗

PubMed1993

Clinical and cytogenetic significance of myelodysplastic syndromes with disease evolution.

We performed a retrospective study of 83 patients with myelodysplastic syndrome (MDS) to clarify the clinical and cytogenetic implications of disease evolution. Twenty-three patients showed disease progression; six of the 11 patients whose disease evolved within 100 days showed complex cytogenetic aberrations and most of them died within 300 days. Of the patients who survived more than 300 days, those with high bone marrow (BM) blast percentages experienced significant disease progression, but we noted no cytogenetic indicators for disease evolution at the later phase. Sixty percent of patients showing karyotypic evolution without disease evolution had deletion-type chromosome changes. The most frequent anomaly in patients with disease evolution who survived more than 300 days was an additional numerical change, whereas patients with disease evolution who survived less than 300 days showed karyotypic instability. It was difficult to predict disease progression for patients whose disease evolved more than 300 days after diagnosis, but in some patients the presence of additional numerical changes was related to disease progression. The cutoff level of early disease evolution was 100 days after diagnosis, and most patients with complex abnormalities survived less than 300 days with or without disease evolution.

Adult↗

PubMed2000

Chromosomal alterations associated with evolution from myelodysplastic syndrome to acute myeloid leukemia.

Several studies have demonstrated the prognostic value of cytogenetic analysis in MDS both for survival and progression to AML. However it is unknown which are the numerical or structural abnormalities required for leukemic transformation. In this report we studied clinically and cytogenetically 127 patients: 125 with primary MDS and two with AML with a previous history of MDS. Thirty-one patients (24%) showed evolution of the disease during the follow-up study. Chromosomal abnormalities found at diagnosis in patients that progressed toward AML included: del(5)(q15), +6, del(6)(q21), t(5;8)(q32;q22),-7, del(7)(q22), der(7)t(1;7)(q10;p10), t(7;11)(p15;p15), +8, del(11)(q23), del(12p), del(3)(q21), del(20)(q12) and complex karyotypes. Eight of these patients were studied cytogenetically during transformation and showed acquisition of chromosomal alterations involving dup(1q), +8, del(11)(q23), and translocations between chromosomes 1 and 8 or 7 and 17. In addition we also observed gain of ploidy and monosomy 21. These results suggest that chromosomal alterations during evolution of the disease include special chromosome gains or abnormalities of chromosomes 1, 7, 8, 11 and 17 with involvement of ETV-1, Hox-A9, Pax 4, MLL genes besides a putative gene mapped at 17q25. We also applied the International Prognostic Scoring System (IPSS) to 114 patients, excluding those submitted to allogeneic bone marrow transplant. Our patients were classified into four distinct risk groups. The analysis of risk groups presented by 27 patients who showed evolution of the disease revealed 18 at the high risk group and four at the intermediate-2 group. From the intermediate-1 risk group only five patients showed evolution of the disease. Three of these patients evolved from RA to RAEB with gain of a del(11)(q23) or an expansion of a del(12)(p12) clone. Our results suggest that some chromosomal alterations are responsible for each step in the evolution of the disease. As the pathway of evolution is not unique it has been very difficult to define what genetic alteration comes first. However from several results in the literature and our own, it seems that some chromosomal alterations may predict the evolution of the disease and are correlated with short survival, as for example the trisomy of chromosome 8, and might be incorporated in the high risk group in the IPSS. This score system has been proved to be useful for predicting survival and evolution from MDS to AML.

Adolescent↗

PubMed1996

Long-term evolution of gut inflammation in patients with spondyloarthropathy.

BACKGROUND & AIMS: Intestinal inflammation has been observed in patients with spondyloarthropathy (SpA). This prospective study reports the evolution of the intestinal inflammation observed in patients with SpA. METHODS: One hundred twenty-three patients with SpA who had undergone initial endoscopy were clinically reassessed. Intestinal evolution was evaluated by ileocolonoscopy and the histological study of biopsy specimens in 49 patients. RESULTS: Articular remission rates were independent of initial gut inflammation and associated with endoscopic and histological remission. Persistent gut inflammation was observed in active joint disease. Gut inflammation rarely disappeared, despite the persistence of articular complaints. Initial chronic gut inflammation implied a high risk of evolution to ankylosing spondylitis. Evolution to inflammatory bowel disease (IBD) was observed in 7% of patients. Mainly patients with initial chronic inflammation and mild complaints of diarrhea were at risk. Sulfasalazine was more frequently needed in the treatment of patients with gut inflammation with a beneficial effect on articular and intestinal evolution but did not prevent evolution to IBD. CONCLUSIONS: This study supports the etiopathogenetic role of the gut in SpA. Presence of chronic gut inflammation and mild complaints of diarrhea implies a high risk of evolution to ankylosing spondylitis and IBD. Sulfasalazine has a beneficial effect on articular activity by controlling gut inflammation, but it cannot prevent evolution to overt IBD.

Adolescent↗

PubMed1980

General theory of evolution.

The biological, neural, cultural and technical evolutions and their phenomena have been explored, and on the basis of our findings the formation of a general theory of evolution has been undertaken. In each of the systems studied, the presence of structural building units, excitable structures and an energy-flow going through the system can be observed. Under the organizing effect of this energy-flow, the spontaneous generation of the replicative information begins and the structures of the system establish functional relations with each other. It can be demonstrated that the evolution of structures has a replicative character. The evolution goes through a phase of non-identical replication, and reaches the phase of identical replication. The parts of the system become separated, that is, compartments develop within it. The replicative information becomes compartmentalized and it converges. As a consequence of the convergence, the compartments compose new structural units which is tantamount to the development of new evolutional levels. The direction of evolution is determined by the growth of replicative information, and this process is concluded when the total system becomes one replicative unit. In the last part of the paper a few of the basic principles of evolution concerning matter, energy and information are drawn up.

Animals↗

PubMed1993

Ubiquitins revisited: further examples of within- and between-locus concerted evolution.

Ubiquitin genes provide a model for studying the effects of concerted evolution on the evolution of a family of short repeated sequences. Previous work has demonstrated the occurrence of within-locus concerted evolution and raised the question of the effectiveness of between-locus concerted evolution for ubiquitin repeats. In this study comparative analysis of additional nucleotide sequences of ubiquitin tandem repeats provides further details of within-locus concerted evolution. Moreover, the availability of multiple polyubiquitin loci and ubiquitin fusion loci within a species makes possible the detection of between-locus concerted evolution. These data indicate that concerted evolution is an effective force for homogenizing repeats between, as well as within, loci.

Animals↗

PubMed1996

Molecular evolution of ruminant lysozymes.

The evolution of a new digestive enzyme, stomach lysozyme, from an antibacterial host defense enzyme provides a link between molecular evolution and organismal evolution. Lysozymes have been recruited at least three times (twice from a conventional lysozyme c and once from a calcium-binding lysozyme c) in vertebrates for functioning in the stomach. The recruitment of lysozyme for its new biological function involved many molecular changes, beyond those required to adapt the protein to function in the stomach. The evolution of the stomach lysozyme gene has been extensively studied in ruminant artiodactyls. In ruminants, the lysozyme c gene has duplicated to yield a family of about ten genes. These duplications allowed: (1) specialization of gene function and (2) increased levels of expression. The ruminant stomach lysozyme genes have evolved in an episodic fashion - there was a period of rapid adaptive sequence evolution, driven by positive selection in the early ruminant, that was followed by an increase in purifying selection upon the well-adapted stomach lysozyme sequence among modern species. Recombination of small portions (exons) of the genes between members of the lysozyme gene family may have aided in adaptive evolution. Evolution to a stomach lysozyme is not irreversible; at least one member of the ruminant stomach lysozyme gene family appears to have reverted to a more ancestral function, yet retains hallmarks of its history as a stomach lysozyme.

Animals↗

PubMed1994

Molecular pathways to parallel evolution: I. Gene nexuses and their morphological correlates.

Aspects of the regulatory interactions among genes are probably as old as most genes are themselves. Correspondingly, similar predispositions to changes in such interactions must have existed for long evolutionary periods. Features of the structure and the evolution of the system of gene regulation furnish the background necessary for a molecular understanding of parallel evolution. Patently "unrelated" organs, such as the fat body of a fly and the liver of a mammal, can exhibit fractional homology, a fraction expected to become subject to quantitation. This also seems to hold for different organs in the same organism, such as wings and legs of a fly. In informational macromolecules, on the other hand, homology is indeed all or none. In the quite different case of organs, analogy is expected usually to represent attenuated homology. Many instances of putative convergence are likely to turn out to be predominantly parallel evolution, presumably including the case of the vertebrate and cephalopod eyes. Homology in morphological features reflects a similarity in networks of active genes. Similar nexuses of active genes can be established in cells of different embryological origins. Thus, parallel development can be considered a counterpart to parallel evolution. Specific macromolecular interactions leading to the regulation of the c-fos gene are given as an example of a "controller node" defined as a regulatory unit. Quantitative changes in gene control are distinguished from relational changes, and frequent parallelism in quantitative changes is noted in Drosophila enzymes. Evolutionary reversions in quantitative gene expression are also expected. The evolution of relational patterns is attributed to several distinct mechanisms, notably the shuffling of protein domains. The growth of such patterns may in part be brought about by a particular process of compensation for "controller gene diseases," a process that would spontaneously tend to lead to increased regulatory and organismal complexity. Despite the inferred increase in gene interaction complexity, whose course over evolutionary time is unknown, the number of homology groups for the functional and structural protein units designated as domains has probably remained rather constant, even as, in some of its branches, evolution moved toward "higher" organisms. In connection with this process, the question is raised of parallel evolution within the purview of activating and repressing master switches and in regard to the number of levels into which the hierarchies of genic master switches will eventually be resolved.

Animals↗

PubMed1976

Chemical evolution of photosynthesis.

The principles of biological evolution of photosynthesis are established, but the ways of chemical evolution are unclear yet. The model systems will help to elucidate the problem. Every type of photosynthesis requires photoreceptor absorbing solar radiation. We studied as photoreceptors inorganic components of Earth crust, some coenzymes and porphyrins of abiogenic and biogenic origin. By the aid of inorganic photosensitizers (TiO2, ZnO) the models of photosystems I and II were constructed. Photochemical activation of some coenzymes may serve as an intermediate step from heterotrophic 'dark' to 'light' metabolism. The further evolution led to the separation of catalytic and photosensitizing functions. Porphin, chlorin and bacteriochlorin were formed by abiogenic synthesis. Magnesium complexes of porphyrins are active being excited by light. They are capable to reversible acceptance or donation of an electron to partner molecule. Excited Mg-complexes of porphyrins (P) are capable to transfer an electron from electron-donor (D) to electron-acceptor (A) accompanied by conversion of light quanta energy into potential chemical energy. The primary electron transfer unit (D-P-A) was incorporated into primary membrane. The transition from random to anisotropic arrangement of (D-P-A) in the membrane was plausable as a step of evolution; charge translocation appeared. (D-P-A) units created in the period of chemical evolution were probably used in the course of biological evolution. The (D-P-A) units were coupled with noncyclic and cyclic electron transfer resulting in ATP formation; coupling of two (D-P-A) units led to H2O oxidation and NADP reduction in photosynthetic organisms. The improvement of pigments biosynthesis created the phenomenon of excitation energy migration from the bulk of the pigment to (D-P-A) unit, being reactive center. The models described points the plausible steps of chemical evolution; the real sequence of events will be probably disclosed in the studies of precambrian rocks and space exploration.

Biological Evolution↗

PubMed1982

[Historic and functional biology: the inadequacy of a system theory of evolution].

In the first half of the 20th century neo-Kantianism in a broad sense proved itself the main conceptual and methodological background of the central European biology. As such it contributed much to the victory on the typological, idealistic-morphological and psycho-vitalistic interpretations of life. On the other hand it could not give tools to the biologists for working out a strictly darwinian evolution theory. Kant's theory of organism was conceived without evolution as a theory of the internal functionality of the organism. There was only some 'play' with the evolutionary differentiation of the species. Since then the disputes around the work of August Weismann, a synthetical evolution theory which is now behind time, arose. This theory developed from coinciding claims, elaborated by geneticists, mathematicians, and by biologists studying development, natural history and systematics. This was done under a strong influence of marxist ideas. Through the interweaving of such different approaches it was possible for this evolutionary synthesis to influence successfully the development of evolution research during more than 40 years. Philosophically speaking modern evolution theory means therefore an aversion, even a positive abolition of Kantian positions. A number of biologists however--as L. von Bertalanffy--refused to adhere to a misinterpreted Kantian methodology and oriented themselves to an approach via system theory, which obtained a place in evolution research. In fact this is a Kantian approach as well. They only repeated the Kantian dilemma of the evolution which can also be found in Lamarck and Hegel. The system theory of the functionality of the organism never reaches to the level of the evolving species, but remains always on the level of epigenetic thinking, because of its philosophical origin. This paper points out the consequences of this still current dilemma. At the same time an all-enclosing reflection on the methodological, epistemological and the important historical questions of evolutionary biology in its scientific context is recommended.

Animals↗

PubMed1997

Constrained evolution with respect to gene overlap of hepatitis B virus.

With the aim of elucidating the evolution of a hepadnavirus family, we constructed molecular phylogenetic trees for 27 strains of hepatitis B virus (HBV) using both the unweighted pair-grouping and neighbor-joining methods. All five gene regions, P, C, S, X, and preS, were used to construct the phylogenetic trees. Using the phylogenetic trees obtained, we classified these strains into five major groups in which the strains were closely related to each other. Our classification reinforced our previous view that genetic classification is not always compatible with conventional classification determined by serological subtypes. Moreover, constraints on the evolutionary process of HBV were analyzed for amino-acid-altering (nonsynonymous) and silent (synonymous) substitutions, because two-thirds of the open reading frame (ORF), P, contains alternating overlapping ORFs. In our unique analysis of this interesting gene structure of HBV, the most frequent synonymous substitutions were observed in the nonoverlapped parts of the P and C genes. On the other hand, the number of synonymous substitutions per nucleotide site for the S gene was quite low and appeared a strongly constrained evolution. Because the P gene overlaps the S gene in a different frame, the low rate of synonymous substitution for the S gene can be explained by the evolutionary constraints which are imposed on the overlapping gene region. In other words, synonymous substitutions in the S gene can cause amino acid changes in its overlapping region in a different frame. Thus, the evolution of HBV is constrained evolutionarily by the overlapping genes. We propose calling this mode of viral evolution "constrained evolution." The evolution of HBV represents a typical constrained evolution.

Amino Acid Sequence↗

PubMed1989

Selection and evolution of bacteriophages in cellstat.

Objectives of this work were as follows: 1. to establish a laboratory experimental system utilizable in a biophysical approach to molecular evolution; and 2. to provide real world parameters to theories of molecular evolution, especially to Eigen's theory of quasi-species. Secretion type bacteriophage fd of E. coli, closely related phages and artificial chimera phages of fd, and a virulent phage Q beta of E. coli were cultured continuously in a specially designed fermenter called a "cellstat". A phage is cultured in a flow of host bacterial cells. Due to its high dilution rate, the mutant cell could not be selected in the cellstat. It was therefore recognized that the cellstat is suitable for study of the selection and evolution process of a bacteriophage under well-defined environmental conditions without interference from host cell mutations. Population dynamics of bacteriophages of various types in the cellstat were studied theoretically by computer simulation and experimentally. A genetically invariable pure population of phage behaves like an open non-linear chemical reaction system. An invariable mixed population shows a selection process, while a variable population generates an evolution process. Kinetic constants describing the dynamics were determined by curve fitting between the theoretical and the experimental curve obtained from competition experiments and from biological relaxation experiments. One of the most important kinetic parameters thus obtained was the selection coefficient, and its dependence on the base sequence of phage DNA. We drew a local landscape of the selection coefficient near the fd sequence on the base sequence space. From this landscape we were able to confirm the importance of slightly deleterious mutants in molecular evolution. We also confirmed the possibility of developing an evolutionary molecular engineering using a cellstat as an evolution reactor and fd phage as a working replicon. Novelties of this work were as follows: 1. the first stable continuous culture of a bacteriophage was achieved with a cellstat; 2. a local landscape of selection coefficient near the fd sequence on the sequence space was the first experimental drawing of such a map; 3. a biological relaxation method was realized to measure kinetic constants of a biological kinetic process, or molecular evolution; and 4. a practical engineering process of evolutionary molecular engineering was proposed.

Bacteriophages↗

PubMed2000

The molecular evolution of signal peptides.

Signal peptides direct mature peptides to their appropriate cellular location, after which they are cleaved off. Very many random alternatives can serve the same function. Of all coding sequences, therefore, signal peptides might come closest to being neutrally evolving. Here we consider this issue by examining the molecular evolution of 76 mouse-rat orthologues, each with defined signal peptides. Although they do evolve rapidly, they evolve about half as fast as neutral sequences. This indicates that a substantial proportion of mutations must be under stabilizing selection. A few putative signal sequences lack a hydrophobic core and these tend to be more slowly evolving than others, indicating even stronger stabilizing selection. However, closer scrutiny suggests that some of these represent mis-annotations in GenBank. It is also likely that some of the substitutions are not neutral. We find, for example, that the rate of protein evolution correlates with that of the mature peptide. This may be a result of compensatory evolution. We also find that signal peptides of immune genes tend to be faster evolving than the average, which suggests an association with antagonistic co-evolution. Previous reports also indicated that the signal peptide of the imprinted gene, Igf2r, is also unusually fast evolving. This, it was hypothesized, might also be indicative of antagonistic co-evolution. Comparison of Igf2r's signal peptide evolution shows that, although it is not an outlier, its rate of evolution is comparable to that of many of the faster evolving immune system signal sequences and 5/6 of the amino acid changes do not conserve hydrophobicity. This is at least suggestive that there is something unusual about Igf2r's signal sequence.

Amino Acid Substitution↗

PubMed2026

Evolution after whole-genome duplication (WGD) drives phenotypic and transcriptomic divergence more than WGD in an autopolyploid herb.

Whole-genome duplication (WGD) is a major driver of plant speciation and often hypothesized to promote rapid adaptation to new or changing environmental conditions. However, the extent to which WGD per se fosters phenotypic and transcriptional novelties, and the relative contribution of WGD-induced changes vs post-WGD evolution to trait differentiation between cytotypes remains poorly understood. Here, we investigated the phenotypic and transcriptomic consequences of WGD and subsequent evolution in the Biscutella laevigata diploid-autotetraploid complex by comparing replicated diploid, synthetic autotetraploids, and natural autotetraploids (originated some 24,000 to 7,000 generations ago) under moderate daily temperature fluctuations (stable) vs. daily heat stress (changing) conditions. WGD led to reduced specific leaf area and slower rosette growth but had no significant effect on biomass. Post-WGD evolution acted in contrasting directions on WGD-induced changes, either reverting traits to diploid-like values or maintaining them in natural autotetraploids. Overall, WGD induced a decrease in fitness that was mitigated by post-WGD evolution, resulting in natural autotetraploids with similar or higher fitness under changing conditions than diploids. While the genetic background modulates the effects of WGD, cytotype-level transcriptomic analyses revealed limited immediate effects of WGD under stable conditions, although heat stress induced different responses across cytotypes. Altogether, our results highlight a complex interplay between immediate WGD-induced and subsequent evolution at the phenotypic and transcriptomic levels, supporting a predominant role of post-WGD evolution in the differentiation of current cytotypes and the adaptive evolution of autotetraploids of B. laevigata.

Genome, Plant↗

PubMed1986

Niche expansion in bacteria: can infectious gene exchange affect the rate of evolution?

Recombination occurs by infectious gene transfer in bacteria, at rates much lower than recombination by sexual reproduction in other organisms. Thus, recombination may accelerate evolution in bacteria only under restricted conditions, such as occur when mutations at several loci are required for the evolution of an expanded ecological niche. Mathematical ("chemostat") models of several such cases--evolution of independence from three limiting essential or "interactive-essential" resources; evolution of the ability to use three new substitutable resources; and evolution of resistance to three growth inhibitors--were analyzed by computer simulation. All combinations of three mutation rates (U) and four values for the "infectious gene transfer rate parameter" (chi) were considered. Recombination accelerated evolution most when U was low and chi was high, but was unlikely to have large effects when chi was low enough to be realistic for natural populations of Escherichia coli. Recombination had the largest effects when resources were substitutable, and in that case could have substantially reduced the chance of random loss of the favored "triple mutant" while it was still rare. The simulations also revealed some interesting features of selection for an expanded niche. Evolution of independence from essential resources occurred more rapidly when the resources were weakly complementary than when they did not interact. Selection for the ability to use all substitutable resources was weak after all intermediate types that used only one or two of the resources had arisen.

Anti-Bacterial Agents↗

PubMed1997

Evolution of the structural repertoire of the human V(H) and Vkappa germline genes.

Variable genes of human Ig are classified in families and clans which reflect the early events of gene duplication in the evolution of the locus. This organization in multiple copies of variable genes plus the somatic processes of recombination and hypermutation allows the immune system to generate an antibody repertoire of great diversity. At present the role that somatic processes play in the generation of that diversity is understood with some detail. It is a matter of hard controversy, however, which selective pressures have shaped the evolution of the germline genes of Ig and, consequently, what the role of this germline component in the generation of the antibody diversity actually is. Previous studies of our group have showed that the structural repertoire of Ig-determined by the canonical structures-is an important factor to determine the recognition properties of the antibodies. Complete knowledge of the sequences of the human V(H) and Vkappa loci is available to analyze the evolution of the structural repertoire of these loci. Two phylogenetic gene trees were built from the functional germline genes and the evolution of the structural repertoire was studied. We report that for both loci the canonical structures are not randomly distributed within the tree. Conversely, it is shown that the evolution of the structural repertoire follows a gradual process of diversification. This indicates a correlation between the evolution of genes and the structural repertoire, although important differences are found in the patterns of evolution of the structural repertoire between V(H) and Vkappa. Based on those results we propose a primordial structural repertoire for V(H) and Vkappa. The general properties and an outline of the three-dimensional structure of this primordial repertoire are given.

Amino Acid Sequence↗

PubMed1981

On the evolution of neurochemical transmission.

A discussion of the evolution of neurochemical transmission is divided into three main topics: evolution of biochemical signalling devices, evolution of neurotransmitter substances, and evolution of signal meaning. Models of signalling devices are developed from a primitive chemoceptive process through open and closed loop communications to a neuronal communications network and to its development into a symbolic logic exchange. The evolution of neurotransmitter substances is extrapolated from experimental evidence which has been obtained under primitive earth atmosphere conditions. Examples from comparative biology suggest that the evolution of transmitter use was not unidirectional and that purine derivatives may well have been the primordial transmitter substances. The classical neurotransmitters, such as acetylcholine and norepinephrine have a limited information content in their molecular structure, whereas inherent message content of peptidergic transmitters is potentially significant. If there are mnemotypic genes, they may be expressed as informational macromolecules which specify behavioral patterns. Such information transfer would represent a second order of neurochemical transmission and its evolution would be closely coupled to that of molecules which contain a universal meaning.

Acetylcholine↗

PubMed1998

Viral genetic evolution in macaques infected with molecularly cloned simian immunodeficiency virus correlates with the extent of persistent viremia.

Genetic evolution of the simian immunodeficiency virus (SIV) envelope glycoprotein was evaluated in a group of six macaques (Macaca nemestrina) infected with the molecularly cloned, moderately pathogenic SIVsm62d. The extent of envelope evolution was subsequently evaluated within the context of the individual pattern of viremia and disease outcome. Two macaques in this cohort developed AIDS by 1.5 years postinoculation (progressors), whereas the remaining four macaques remained asymptomatic (nonprogressors). Compared with the nonprogressor macaques, the two progressor macaques exhibited higher persistent plasma viremia, higher homologous neutralizing antibody titers, and more extensive mutation and evolution in the V1 region of envelope. Although clearly distinct in each of these parameters from the progressors, the four nonprogressors exhibited more individual variability with respect to the extent of persistent viremia and genetic evolution of the V1 region of envelope. The extent of V1 envelope varied from no apparent V1 evolution in a macaque with good viral containment to extensive evolution in one macaque with persistent viremia. This study underscores the critical role of persistent replication in the genetic evolution of SIV.

Amino Acid Sequence↗