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171.
Gene flow does not prevent personality and morphological differentiation between two blue tit populations
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![点击此处可从《Journal of evolutionary biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Gabrielle Dubuc‐Messier Samuel P. Caro Charles Perrier Kees van Oers Anne Charmantier 《Journal of evolutionary biology》2018,31(8):1127-1137
Understanding the causes and consequences of population phenotypic divergence is a central goal in ecology and evolution. Phenotypic divergence among populations can result from genetic divergence, phenotypic plasticity or a combination of the two. However, few studies have deciphered these mechanisms for populations geographically close and connected by gene flow, especially in the case of personality traits. In this study, we used a common garden experiment to explore the genetic basis of the phenotypic divergence observed between two blue tit (Cyanistes caeruleus) populations inhabiting contrasting habitats separated by 25 km, for two personality traits (exploration speed and handling aggression), one physiological trait (heart rate during restraint) and two morphological traits (tarsus length and body mass). Blue tit nestlings were removed from their population and raised in a common garden for up to 5 years. We then compared adult phenotypes between the two populations, as well as trait‐specific Qst and Fst. Our results revealed differences between populations similar to those found in the wild, suggesting a genetic divergence for all traits. Qst–Fst comparisons revealed that the trait divergences likely result from dissimilar selection patterns rather than from genetic drift. Our study is one of the first to report a Qst–Fst comparison for personality traits and adds to the growing body of evidence that population genetic divergence is possible at a small scale for a variety of traits including behavioural traits. 相似文献
172.
Model‐driven design of a minimal medium for Akkermansia muciniphila confirms mucus adaptation
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![点击此处可从《Microbial biotechnology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Kees C. H. van der Ark Steven Aalvink Maria Suarez‐Diez Peter J. Schaap Willem M. de Vos Clara Belzer 《Microbial biotechnology》2018,11(3):476-485
The abundance of the human intestinal symbiont Akkermansia muciniphila has found to be inversely correlated with several diseases, including metabolic syndrome and obesity. A. muciniphila is known to use mucin as sole carbon and nitrogen source. To study the physiology and the potential for therapeutic applications of this bacterium, we designed a defined minimal medium. The composition of the medium was based on the genome‐scale metabolic model of A. muciniphila and the composition of mucin. Our results indicate that A. muciniphila does not code for GlmS, the enzyme that mediates the conversion of fructose‐6‐phosphate (Fru6P) to glucosamine‐6‐phosphate (GlcN6P), which is essential in peptidoglycan formation. The only annotated enzyme that could mediate this conversion is Amuc‐NagB on locus Amuc_1822. We found that Amuc‐NagB was unable to form GlcN6P from Fru6P at physiological conditions, while it efficiently catalyzed the reverse reaction. To overcome this inability, N‐acetylglucosamine needs to be present in the medium for A. muciniphila growth. With these findings, the genome‐scale metabolic model was updated and used to accurately predict growth of A. muciniphila on synthetic media. The finding that A. muciniphila has a necessity for GlcNAc, which is present in mucin further prompts the adaptation to its mucosal niche. 相似文献
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Janneke C. Alers Pieter-Jaap Krijtenburg Kees J. Vissers Sheila K. Krishnadath Fré T. Bosman Herman van Dekken 《Histochemistry and cell biology》1995,104(6):479-486
A comparative study was performed of interphase in situ hybridization (ISH) to deparaffinized 4-m tissue sections and nuclear suspensions from eight prostatic adenocarcinomas, as well as one normal prostatic control. Whole nuclear suspensions were derived from the same tumor areas to evaluate differences of ISH to truncated versus whole nuclei. DNA probes specific for the centromeres of chromosome 1, 7, 8, 10, and Y were used for detection of numerical chromosomal changes and aneuploidy. In six adenocarcinomas chromosome aberrations (+7, +8, –8, –10, –Y) were seen. However, ISH to sections revealed focal aberrations (–10, –Y) in four cases that could not be distinguished in the suspensions. Chromosomal alterations occurring in larger tumor areas were also detected in the nuclear suspensions. Chromosome copy number changes, especially gains, were better discriminated in the nuclear suspensions. The rate of ISH aneuploidy seen in nuclear suspensions corresponded with that observed in the tissue sections (P<0.01). Ploidy patterns as assessed by ISH to sections and nuclear suspensions were in concordance with DNA flow cytometry (bothP<0.001). We conclude that both section and suspension ISH were able to accurately detect aneuploidy and numerical chromosomal aberrations occurring in larger histological areas. However, section ISH was also capable of revealing (small) focal cytogenetic abnormalities, due to a precise analysis of only target cells. Focal abnormalities were not detected by suspension ISH, probably due to an admixture of non-aberrant tumor cells and stromal elements. 相似文献
175.
Kees Kersting 《Aquatic Ecology》1997,31(1):29-35
A microecosystem consisting of three subsystems roughly representing the trophic levels of autotrophs, herbivores and decomposers was developed. A recirculating flow of water connected the three subsystems. Analysis of the data over a period of 7500 days indicates that the system has remained in the same state and has the prospect of being immortal. The Daphnia population showed periods of large oscillations, but also long periods of almost constant numbers. External factors were responsible for the initiation of the oscillations. The threshold food level for population increase was lower than mostly is found for individual growth, indicating adaptation to low food concentrations. 相似文献
176.
Low but contrasting neutral genetic differentiation shaped by winter temperature in European great tits
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![点击此处可从《Biological journal of the Linnean Society. Linnean Society of London》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Mélissa Lemoine Kay Lucek Charles Perrier Verena Saladin Frank Adriaensen Emilio Barba Eduardo J. Belda Anne Charmantier Mariusz Cichoń Tapio Eeva Arnaud Grégoire Camilla A. Hinde Arild Johnsen Jan Komdeur Raivo Mänd Erik Matthysen Ana Cláudia Norte Natalia Pitala Ben C. Sheldon Tore Slagsvold Joost M. Tinbergen János Török Richard Ubels Kees van Oers Marcel E. Visser Blandine Doligez Heinz Richner 《Biological journal of the Linnean Society. Linnean Society of London》2016,118(3):668-685
Gene flow is usually thought to reduce genetic divergence and impede local adaptation by homogenising gene pools between populations. However, evidence for local adaptation and phenotypic differentiation in highly mobile species, experiencing high levels of gene flow, is emerging. Assessing population genetic structure at different spatial scales is thus a crucial step towards understanding mechanisms underlying intraspecific differentiation and diversification. Here, we studied the population genetic structure of a highly mobile species – the great tit Parus major – at different spatial scales. We analysed 884 individuals from 30 sites across Europe including 10 close‐by sites (< 50 km), using 22 microsatellite markers. Overall we found a low but significant genetic differentiation among sites (FST = 0.008). Genetic differentiation was higher, and genetic diversity lower, in south‐western Europe. These regional differences were statistically best explained by winter temperature. Overall, our results suggest that great tits form a single patchy metapopulation across Europe, in which genetic differentiation is independent of geographical distance and gene flow may be regulated by environmental factors via movements related to winter severity. This might have important implications for the evolutionary trajectories of sub‐populations, especially in the context of climate change, and calls for future investigations of local differences in costs and benefits of philopatry at large scales. 相似文献
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178.
M. Fernandez M. House S. Jambawalikar N. Zork J. Vink R. Wapner 《Computer methods in biomechanics and biomedical engineering》2016,19(4):404-417
Preterm birth is a strong contributor to perinatal mortality, and preterm infants that survive are at risk for long-term morbidities. During most of pregnancy, appropriate mechanical function of the cervix is required to maintain the developing fetus in utero. Premature cervical softening and subsequent cervical shortening are hypothesized to cause preterm birth. Presently, there is a lack of understanding of the structural and material factors that influence the mechanical function of the cervix during pregnancy. In this study we build finite element models of the pregnant uterus, cervix, and fetal membrane based on magnetic resonance imagining data in order to examine the mechanical function of the cervix under the physiologic loading conditions of pregnancy. We calculate the mechanical loading state of the cervix for two pregnant patients: 22 weeks gestational age with a normal cervical length and 28 weeks with a short cervix. We investigate the influence of (1) anatomical geometry, (2) cervical material properties, and (3) fetal membrane material properties, including its adhesion properties, on the mechanical loading state of the cervix under physiologically relevant intrauterine pressures. Our study demonstrates that membrane–uterus interaction, cervical material modeling, and membrane mechanical properties are factors that must be deliberately and carefully handled in order to construct a high quality mechanical simulation of pregnancy. 相似文献
179.
180.
Kees Kersting 《Hydrobiologia》1983,107(2):165-168
In a polder ditch with a water depth of 50 cm, oxygen and temperature were measured continuously during 24 hours at 10 cm above the bottom and 10 cm below the surface. Two examples are given in which the diel oxygen curve of the lower electrode was bimodal. The curve of the upper electrode was unimodal in both cases. The occurrence of the bimodal curve could be explained by the turnover of the stratified water column after the surface started to cool in the late afternoon. 相似文献