Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “differential selection”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 829 records · Page 46Linked to original sources

Assessment of weighting methodology for the National Comorbidity Survey.

The authors studied weighting adjustments for the National Comorbidity Survey (1990-1992), a large-scale national epidemiologic investigation of the prevalence, risk factors, and consequences of psychiatric morbidity and comorbidity in the United States. Weighting adjustments for differential selection within households, new construction, unit nonresponse, and poststratification were examined separately and in combination. Specific issues addressed included the magnitude of the bias incurred from ignoring the weights, the added variance from weighting and how well this was predicted by simple formulae, and the performance of methods for trimming the weights. Weights had quite modest effects on point estimates of prevalences but resulted in major increases in variance unless trimmed. The weights after trimming and poststratification appeared to work well. It is suggested that the added variance from weighting be carefully monitored in similar surveys. Alternatives to the use of trimming for controlling variance are worth exploring.

Analysis of Variance↗

Patterns of genetic diversification within the Adh gene family in the grasses (Poaceae).

We investigated the evolutionary dynamics of the Adh gene family within the grasses (Poaceae), with the goal of using molecular evolutionary tools to understand the process of gene family diversification. We analyzed 21 Adh sequences representing a broad array of grasses. Phylogenetic analyses suggested that Adh duplicated into Adh1 and Adh2 before the radiation of the grasses roughly 65 MYA. Gene structure, including intron length, has varied little over this period. Conservation of intron length prompted investigation into the dynamics of intron evolution, particularly the ability of intron sequences to form secondary structures. Intron sequences did not have an extremely high or low minimum free energy of folding relative to permuted sequences, suggesting that individual Adh introns do not evolve under secondary structural constraints. For coding sequences, the diversification of Adh1 and Adh2 was marked by a shift in third-position G + C content. This shift may reflect differential selection for codon use. Diversification between Adh1 and Adh2 was also typified by a shift in nonsynonymous nucleotide substitution rates, but there was no evidence that relatively fast nonsynonymous nucleotide substitution rates in the Adh2 clade were a product of diversifying selection. Gene conversion may have played a role in retarding diversification of Adh1 and Adh2 in rice, but there is no evidence of gene conversion between paralogs in other taxa. Although the reasons for retention of two functional Adh genes remain obscure, we propose that a shift in gene expression was important for the retention of the two Adh gene copies within the grasses.

Alcohol Dehydrogenase↗

Adipose tissue energy metabolism: altered gene expression profile of mice subjected to long-term caloric restriction.

We investigated the influences of short-term and lifespan-prolonging long-term caloric restriction (LCR) on gene expression in white adipose tissue (WAT). Over 11,000 genes were examined using high-density oligonucleotide microarrays in four groups of 10- to 11-month-old male C57Bl6 mice that were either fasted for 18 h before death (F), subjected to short-term caloric restriction for 23 days (SCR), or LCR for 9 months and compared with nonfasted control (CO) mice. Only a few transcripts of F and SCR were differentially expressed compared with CO mice. In contrast, 345 transcripts of 6,266 genes found to be expressed in WAT were altered significantly by LCR. The expression of several genes encoding proteins involved in energy metabolism was increased by LCR. Further, many of the shifts in gene expression after LCR are known to occur during adipocyte differentiation. Selected LCR-associated alterations of gene expression were supported by quantitative reverse transcriptase-polymerase chain reaction, histology, and histochemical examinations. Our data provide new insights on the metabolic state associated with aging retardation by LCR.

Adipose Tissue↗

Therapy for small cell and non-small cell lung cancer.

This review addresses means for improving treatment results in small cell and non-small cell lung cancer. In small cell lung cancer lactate dehydrogenase and neuron-specific enolase seem to be important prognostic factors that may reflect not only tumor load but also growth rate. Chemotherapy seems to induce or select differentiated cells in small cell lung cancer, which focuses attention on other treatment modalities such as drugs, which can induce terminally differentiated nonproliferating cells. Scheduling of chemotherapy may improve survival, especially in extensive disease patients. Exciting new techniques for tumor targeting by a radiolabelled somatostatin-analogue and radiolabelled murine anti-epidermal growth factor are reported. The possible adverse effect of heterologous blood transfusions on survival after surgery of stage I and II non-small cell lung cancer remains a very important subject for investigation to solve the essential question whether the need for transfusion or the transfusion itself is the adverse prognostic factor. A possible improvement of survival of non-small cell lung cancer patients by chemotherapy should be investigated in patients with an excellent performance score and a small tumor load, eg, stage IIIa and IIIb patients. Neoadjuvant chemotherapy in such patients may improve survival but a better and especially more uniform design of the trials is urgently needed. Finally, the development of techniques to palliate terminally ill patients quickly and easily by reopening a closed bronchial lumen should be encouraged.

Carcinoma, Non-Small-Cell Lung↗

Interrelationships of relative risks of birth defects in embryonic and fetal deaths, in livebirths, and in all conceptuses.

Most studies of associations with birth defects are undertaken in livebirths. An observed association in livebirths different from unity may be compatible with no association in conceptuses if "balanced" by a particular relative risk in embryonic and fetal deaths. We derived formulae to address the following queries: (1) If one observes in livebirths a relative risk of birth defect, tau def,lb, then, with what combinations of relative risk of defect in embryonic and fetal deaths, tau def,efd, and in all conceptuses, tau def, is this value compatible? (2) What balancing relative risk in embryonic and fetal deaths is predicted if there is no causal association in all conceptuses? (3) Under what circumstances is there no relative risk in embryonic and fetal deaths that can balance an observed relative risk in livebirths? We present an expression for tau def,efd in terms of five other variables: tau def,lb, tau def, and tau efd (the relative risk of embryonic or fetal death), and the lethalities of the average (unexposed) conceptus and of the (unexposed) defective conceptus. This equation enables one to derive the balancing relative risk in embryonic and fetal deaths, bal tau def,efd, which is the value of tau def,efd when tau def = 1.0. If bal tau def,efd is negative, no such balancing relative risk exists, and any observed association in livebirths is incompatible with a null association in all conceptuses, that is, the association cannot be explained completely by differential selection of conceptuses with defect.

Abortion, Spontaneous↗

Evidence for late stage compartmentalization of HIV-1 resistance mutations between lymph node and peripheral blood mononuclear cells.

OBJECTIVE: To determine the overall distribution of drug-resistance mutations to nucleoside reverse transcriptase inhibitors of HIV strains recovered from the lymph nodes (LN) and peripheral blood mononuclear cell (PBMC) compartments of four HIV-infected patients receiving zidovudine and didanosine and to compare them with antiretroviral-naive patients. DESIGN: Molecular comparison of major and minor HIV-1 env and pol region variants residing in LN and PBMC compartments. MATERIALS AND METHODS: Proviral DNA sequences were amplified by PCR from both PBMC and LN compartments, cloned into PGEM-T II Easy vector and sequenced. The clones were subjected to molecular and phylogenetic analysis. RESULTS: Comparison of PBMC and LN-derived HIV-1 variants in the env V3 region showed that nucleotide and amino acid variability was a characteristic feature of LN-derived variants. In contrast, a majority of resistance mutations to reverse transcriptase inhibitors were localized in the PBMC compartment rather than in LN, which is thought to be a reservoir of HIV. CONCLUSIONS: Distinct compartmentalization or independent evolution of pol and env gene variants between LN and PBMC could be due to the differential selection pressure imposed by the combination drug regimen, hence the bimodal distribution of resistance variants between LN and PBMC compartments.

Anti-HIV Agents↗

Distribution of functional HIV-specific CD8 T lymphocytes between blood and secondary lymphoid organs after 8-18 months of antiretroviral therapy in acutely infected patients.

OBJECTIVES: To assess whether drug-induced suppression of the plasma viral load is associated with selective differential distribution of virus-specific CD8 T cells between the blood and secondary lymphoid organs. METHODS: HIV-specific CD8 T lymphocyte responses were quantified in matched peripheral blood and lymph node samples from seven patients starting treatment shortly after infection, who received antiretroviral therapy (ART) for a median of 14 months. Cells recovered from samples were subjected to IFN-gamma ELISPOT analysis. A series of synthetic peptides corresponding to previously characterized cytotoxic T lymphocyte epitopes restricted by HLA I molecules present in each patient were used as antigens, together with appropriate positive and negative controls. RESULTS: HIV-specific CD8 T lymphocyte responses were found in six of the seven patients. The observed frequencies of HIV-specific CD8 T lymphocytes and the pattern of epitope recognition was identical within the two compartments. These results also confirm the observation that functional HIV-specific CD8 T cells are preserved on ART in most patients initiating treatment at the time of primary HIV-1 infection. CONCLUSION: This investigation demonstrated that patterns of antigenic immunodominance as well as frequencies of HIV-specific CD8 T lymphocytes are similar in blood and lymphoid tissue compartments in HIV-infected individuals. These findings support current approaches to the identification of HIV-specific CD8 T lymphocyte reactivity based on leukocytes isolated from blood even in patients with ART-induced suppression of viral load.

Anti-HIV Agents↗

The expert consensus guideline series. Treatment of behavioral emergencies 2005.

OBJECTIVES: Due to inherent dangers and barriers to research in emergency settings, few data are available to guide clinicians about how best to manage behavioral emergencies. Key constructs such as agitation are poorly defined. This lack of empirical data led us to undertake a survey of expert opinion, results of which were published in the 2001 Expert Consensus Guidelines on the Treatment of Behavioral Emergencies. Several second-generation (atypical) antipsychotics (SGAs) are now available in new formulations for treating behavioral emergencies (e.g., intramuscular [i.m.] olanzapine and ziprasidone; rapidly dissolving tablets of olanzapine and risperidone). Critical questions face the field. The SGAs are significantly different from the FGAs and from each other and have not been studied in unselected patients as were the FGAs. Can the SGAs can be thought of as a class, do all antipsychotics have similar anti-agitation effects in different conditions, and, if equally effective, what limits might their safety profiles impose? Should antipsychotics be used more specifically to treat psychotic conditions, while benzodiazepines (BNZs) alone are used nonspecifically? Few data are available concerning combinations of SGAs and BNZs, and findings concerning the traditional combination of haloperidol plus a BNZ may not be relevant to combinations with SGAs. The culture is also evolving with more emphasis on patient involvement in treatment decisions. An international consensus has been developing that calming rather than sedation is the appropriate endpoint of behavioral emergency interventions. We undertook a new survey of expert opinion to update recommendations from the earlier survey. METHOD: A written survey of 61 questions (1,020 options) was mailed to 50 experts in the field, 48 (96%) of whom completed it. The survey sought to define level of agitation at which emergency interventions are appropriate, scope of assessment depending on urgency and patients' ability to cooperate, guiding principles for selecting interventions, and appropriate physical and medication strategies at different levels of diagnostic confidence for a variety of provisional diagnoses and complicating conditions. A modified version of the RAND Corporation's 9-point scale for rating appropriateness of medical decisions was used to score most options. Consensus was defined as a non-random distribution of scores by chi-square "goodness-of-fit" test. We assigned a categorical rank (first line/preferred, second line/alternate, third line/usually inappropriate) to each option based on the 95% confidence interval around the mean. Ratings were used to develop guidelines for preferred strategies in key clinical situations. This study received financial support from multiple sponsors, with the panel kept blind to sponsorship to reduce possible bias. Medication ratings were based on responses of only those respondents with direct experience with each drug. In reporting practice patterns, the panel was asked to respond based on actual data rather than estimates. RESULTS: The expert panel reached consensus on 78% of the options rated on the 9-point scale. The responses suggest that physicians can make provisional diagnoses with some confidence and that pharmacological and nonpharmacological interventions are selected differentially based on diagnosis and other salient demographic and medical features. BNZs are recommended when no data are available, when there is no specific treatment (e.g., personality disorder), or when they may have specific benefits (e.g., intoxication). No single SGA emerges as a nonspecific replacement for haloperidol; instead, different SGAs are preferred in various circumstances consistent with current evidence. To the degree that haloperidol is recommended, it is almost always in combination with a BNZ; haloperidol alone is preferred only in the medically compromised. In contrast, the SGAs are more often recommended for use alone, and the panel would avoid combining BNZs with some SGAs. Oral risperidone alone or combined with a BNZ receives strong support in a variety of situations. Oral olanzapine was rated very similarly to risperidone, with slightly higher ratings than risperidone in situations where it has been studied (e.g., schizophrenia, mania) and slightly lower ratings where it has not been studied or safety may be a concern; there was less support for combining oral olanzapine with a BNZ. For oral treatment of agitation related to schizophrenia or mania, olanzapine alone, risperidone alone or combined with a BNZ, and haloperidol plus a BNZ are first line, with strong support also for combining divalproex with the antipsychotic for presumed mania. Oral ziprasidone and quetiapine generally received similar second-line ratings in most situations. If a parenteral agent is needed, i.m. olanzapine alone received somewhat more support than i.m. ziprasidone alone; however, there was more support for i.m. ziprasidone alone or combined with a BNZ than for i.m. olanzapine plus a BNZ, probably reflecting safety concerns. For example, for a provisional diagnosis of schizophrenia, first-line parenteral options are i.m. olanzapine or ziprasidone alone or i.m. haloperidol or ziprasidone combined with a BNZ. Neither of the new parenteral formulations received as much support as traditional agents (i.m. BNZs, i.m. haloperidol) when no data are available or the diagnosis involves medical comorbidity or intoxication. When initial intervention with risperidone, ziprasidone, or haloperidol is unsuccessful, the panel recommended adding a BZD to the antipsychotic. However, when initial treatment with olanzapine or quetiapine is unsuccessful, increasing the dosage is recommended. Perphenazine was consistently rated second line and droperidol and chlorpromazine received third-line ratings throughout. CONCLUSIONS: Within the limits of expert opinion and with the expectation that future research data will take precedence, these guidelines suggest that the SGAs are now preferred for agitation in the setting of primary psychiatric illnesses but that BNZs are preferred in other situations.

Aggression↗

Compartmentalization of HIV-1 in the central nervous system: role of the choroid plexus.

OBJECTIVES: To determine the genetic and phenotypic composition of HIV-1 found in the choroid plexus (CPx) and its relationship to virus in the brain and peripheral lymphoid tissue. DESIGN: Phenotypic and molecular comparisons of HIV-1 found in autopsy brain, CPx, and spleen tissues. METHODS: HIV-1 was co-cultured from matched postmortem brain (basal ganglia), CPx, and spleen tissues of AIDS patients with and without HIV-associated encephalitis and dementia. Viral phenotypes were determined by infection of monocyte-derived macrophages, MT-2 or co-receptor-specific cell lines. Viral env and pol sequences were determined from genomic DNA isolated directly from tissues or co-cultures, and phylogenetic comparisons were performed. RESULTS: CCR5-utilization was the most prevalent viral tropism found in all tissues, although spleen isolates also displayed CXCR4 usage. Viruses isolated from CPx consisted of both peripheral and brain-like virus, but were more related phenotypically and genetically to those found in the brain. Mutations found in the pol gene that could confer drug resistance to brain and CPx isolates were similar to those found in the periphery. CONCLUSION: The CPx contained replication-competent virus that was most similar, although distinct, from that found in the brain. It also contained some viruses with high similarity to those of peripheral origin. Compartmentalization of viral env and pol sequences indicated that differential selective pressures exist in each tissue examined. These studies suggest that the CPx may provide an environment that promotes the evolution of drug-resistant strains with central nervous system tropism, although it is unlikely to be a reservoir for archival HIV-1 variants.

AIDS Dementia Complex↗

Dynamics and evolution: evolutionarily stable attractors, invasion exponents and phenotype dynamics.

We extend the ideas of evolutionary dynamics and stability to a very broad class of biological and other dynamical systems. We simultaneously develop the general mathematical theory and a discussion of some illustrative examples. After developing an appropriate formulation for the dynamics, we define the notion of an evolutionary stable attractor (ESA) and give some samples of ESAS with simple and complex dynamics. We discuss the relationship between our theory and that for ESSS in classical linear evolutionary game theory by considering some dynamical extensions. We then introduce and develop our main mathematical tool, the invasion exponent. This allows analytical and numerical analysis of relatively complex situations, such as the coevolution of multiple species with chaotic population dynamics. Using this, we introduce the notion of differential selective pressure which for generic systems is nonlinear and characterizes internal ESAS. We use this to analytically determine the ESAS in our previous examples. Then we introduce the phenotype dynamics which describe how a population with a distribution of phenotypes changes in time with or without mutations. We discuss the relation between the asymptotic states of this and the ESAS. Finally, we use our mathematical formulation to analyse a non-reproductive form of evolution in which various learning rules compete and evolve. We give a very tentative economic application which has interesting ESAS and phenotype dynamics.

Animals↗

Molecular analysis of a serotype 8 human astrovirus genome.

Human astroviruses are an important cause of gastroenteritis. As part of a molecular epidemiological study carried out in Mexico a human astrovirus isolate, Yuc-8, was adapted to grow in CaCo-2 cells, and its entire genome was sequenced. A 15 amino acid deletion in ORF1a, which has been associated with adaptation of astroviruses to grow in cells other than CaCo-2, was present in Yuc-8. Comparative sequence analysis of the Yuc-8 ORF2 with reported human astrovirus sequences revealed that this isolate belongs to genotype (serotype) 8. Two distinct domains in ORF2 were observed: an amino-terminal domain (residues 1 to 415), with identities higher than 81% among the strains analysed, and a carboxy-terminal domain (residues 416 to 782) with identities between 36 and 60%. Two non-superimposable phylogenetic trees were generated by separate analysis of these two domains, suggesting that a differential selective pressure is exerted along the structural polyprotein.

Amino Acid Sequence↗

Simulation of the rat intestinal ecosystem using a two-stage continuous culture system.

To investigate the ecological mechanisms governing the community structure of the gut microbial ecosystem, we have attempted to simulate the rat gut ecosystem in vitro using a two-stage continuous culture. Extensive sampling of the rat hindgut has established a set of criteria with which the in vitro system may be compared. This paper discusses one of the criteria, the community composition and structure in vivo and in vitro. The experiments indicated that a gut microbial ecosystem could be satisfactorily mimicked in vitro. This was achieved using a two-stage continuous culture employing differential selection of species between the two stages on the basis of pH differences combined with cell recycling between stages.

Animals↗

Global haplotype diversity in the human insulin gene region.

The insulin minisatellite (INS VNTR) has been intensively analyzed due to its associations with diseases including diabetes. We have previously used patterns of variant repeat distribution in the minisatellite to demonstrate that genetic diversity is unusually great in Africans compared to non-Africans. Here we analyzed variation at 56 single nucleotide polymorphisms (SNPs) flanking the minisatellite in individuals from six populations, and we show that over 40% of the total genetic variance near the minisatellite is due to differences between Africans and non-Africans, far higher than seen in most genomic regions and consistent with differential selection acting on the insulin gene region, most likely in the non-African ancestral population. Linkage disequilibrium was lower in African populations, with evidence of clustering of historical recombination events. Analysis of haplotypes from the relatively nonrecombining region around the minisatellite revealed a star-shaped phylogeny with lineages radiating from an ancestral African-specific haplotype. These haplotypes confirmed that minisatellite lineages defined by variant repeat distributions are monophyletic in origin. These analyses provide a framework for a cladistic approach to future disease association studies of the insulin region within both African and non-African populations, and they identify SNPs which can be rapidly analyzed as surrogate markers for minisatellite lineage.

Africa↗

Initial stages of reproductive isolation in two species of the endangered Sonoran topminnow.

Long-term geographic isolation can result in reproductive incompatibilities due to forces such as mutation, genetic drift, and differential selection. In the Sonoran topminnow, molecular genetic studies of mtDNA, microsatellites, and MHC genes have shown that the endangered Gila and Yaqui topminnows are substantially different, suggesting that divergence took place approximately two million years ago. Here we examined hybrid crosses and backcrosses between these two allopatric taxa to evaluate the accumulation of postmating barriers to reproduction. These results are then compared with results from a previous study where male topminnows were shown to mate assortatively with conspecific females. Despite their preference for conspecific mates, both types of interspecific crosses successfully produced offspring. There was evidence of reduced hybrid fitness, including smaller mean brood size and male-biased sex ratio, for some classes of backcrosses. Brood sizes and interbrood intervals varied significantly when hybrids were subdivided into different cross categories. Our results illustrate the importance of distinctly defining hybrid classes in studies of reproductive isolation. To our knowledge, this is the first such detailed evolutionary analysis in endangered fish taxa.

Animals↗

Use of RT-PCR and DNA microarrays to characterize RNA recovered by non-invasive tape harvesting of normal and inflamed skin.

We describe a non-invasive approach for recovering RNA from the surface of skin via a simple tape stripping procedure that permits a direct quantitative and qualitative assessment of pathologic and physiologic biomarkers. Using semi-quantitative RT-PCR we show that tape-harvested RNA is comparable in quality and utility to RNA recovered by biopsy. It is likely that tape-harvested RNA is derived from epidermal cells residing close to the surface and includes adnexal structures and present data showing that tape and biopsy likely recover different cell populations. We report the successful amplification of tape-harvested RNA for hybridization to DNA microarrays. These experiments showed no significant gene expression level differences between replicate sites on a subject and minimal differences between a male and female subject. We also compared the array generated RNA profiles between normal and 24 h 1% SLS-occluded skin and observed that SLS treatment resulted in statistically significant changes in the expression levels of more than 1,700 genes. These data establish the utility of tape harvesting as a non-invasive method for capturing RNA from human skin and support the hypothesis that tape harvesting is an efficient method for sampling the epidermis and identifying select differentially regulated epidermal biomarkers.

Actins↗

A critical review of the causes of death among post-mortem toxicological investigations: analysis of 34 buprenorphine-associated and 35 methadone-associated deaths.

AIMS: To assess the trends in the number, mortality and the nature of forensic cases involving toxicological detection of buprenorphine or methadone among toxicological investigations performed in Paris from June 1997 to June 2002. DESIGN: Retrospective, 5 year study with review of premortem data, autopsy, police reports, hospital data, and post-mortem toxicological analyses. SETTING AND PARTICIPANTS: 34 forensic cases of buprenorphine and 35 forensic cases of methadone detection among 1600 toxicological investigations performed at the Laboratory of Toxicology in the Medical Examiner's Office in Paris. MEASUREMENTS AND RESULTS: Therapeutic, toxic or lethal drug concentrations were defined based upon the results of blood analyses and the published literature. Drug concentrations were cross-referenced with other available ante- and post-mortem data. Subsequently, we classified a 'clear responsibility', 'possible responsibility' or 'not causative' role for buprenorphine or methadone in the death process, or 'no explanation of death'. Buprenorphine and methadone can be regarded as being directly implicated in, respectively, four of 34 death cases (12%) and three of 35 death cases (9%), and their participation in the lethal process is strongly plausible in eight (buprenorphine) and 11 (methadone) additional deaths. CONCLUSIONS: Analysis of causes of death reveals the difficulties in determining the role of substitution drugs in the death process, as many other factors may be involved, including circumstances surrounding death, past history, differential selection of subjects into either substitution modality and concomitant intake of other drugs (especially benzodiazepines and neuroleptics). The potential for synergistic or additive actions by other isolated molecules-particularly opioids, benzodiazepines, other psychotropes and alcohol-must be also considered.

Adult↗

Rheumatoid synovial fluid reconstitutes the B-cell defect in CBA/N mice.

Synovial fluid from patients with rheumatoid arthritis (RA-SF) contains a biological activity which can replace T cells for activation of antibody secretion in human blood lymphoid cells and which can also induce the selective differentiation of IgG2b-secreting cells in lipopolysaccharide (LPS)-pre-activated mouse spleen cells. The B-cell activity of this factor was studied in CBA/N mice which have an X-linked B-cell immunodeficiency which manifests itself as a defective humoral response to certain thymus-independent antigens (TI-2). RA-SF has now been shown to reconstitute partly the B-cell deficiency in CBA/N splenic B cells in vitro. Addition of RA-SF to LPS-pretreated cell cultures results in IgG2b secretion in CBA/N spleen cells as well. In contrast to cells from normal CBA mice, cells from CBA/N mice cannot respond to interleukin 4 (IL-4) after addition of LPS with production of IgG1 antibodies in vitro. However, the addition of RA-SF completely restores a normal IL-4-induced IgG1 response. No other biologically active factors have been shown to allow the production of IgG antibody producing cells in CBA/N splenic B cells. It is postulated that the xid immunodeficiency could be the result of a deficient production of a biological activity which is abundant in RA-SF.

Animals↗

Genetic and morphological data supporting the hypothesis of adaptive radiation in the endemic fish of Lake Matano.

Adaptive radiation resulting from differential selection acting on functional features is believed to be an important source of biodiversity. In this study, morphometric measures and mitochondrial DNA are used to test for adaptive radiation within four fish genera (Glossogobius, Oryzias, Dermogenys and Telmatherina) endemic to an ancient island lake (Lake Matano, Sulawesi, Indonesia), using the framework proposed by Schluter (The Ecology of Adaptive Radiation, Oxford University Press, 2000). We demonstrate common ancestry and rapid divergence in one genus (Telmatherina) based on 560 bp of 16S sequence data. We found higher levels of variation in feeding-related traits (N = 8) for Telmatherina relative to the other genera, while no differences were found for sexual display traits (N = 8) or neutral morphological traits (N = 8). Telmatherina also had the highest number of distinct colouration patterns among the four genera. These data, combined with the very low productivity of the lake, are indicative of selection driving adaptive radiation. The morphometric divergence in the Telmatherina likely results from selection acting on feeding traits in this low productivity lake, leading to trophic specialization among closely related morphotypes. These results provide indirect but compelling data supporting the adaptive radiation of Telmatherina in this system.

Adaptation, Biological↗