Feed aggregator

We may be overdue a massive war, says a statistical analysis

Genetically modified organisms (GMO) - пт, 2018-02-23 13:12
Since the end of the second world war a “long peace” has prevailed around the world, but far from being a new era in history it could just be a statistical fluke
Категории: Science and society

We may be overdue a massive war, says a statistical analysis

Genetics - пт, 2018-02-23 13:12
Since the end of the second world war a “long peace” has prevailed around the world, but far from being a new era in history it could just be a statistical fluke
Категории: Biology

We may be overdue a massive war, says a statistical analysis

HIV and AIDS - пт, 2018-02-23 13:12
Since the end of the second world war a “long peace” has prevailed around the world, but far from being a new era in history it could just be a statistical fluke
Категории: Healthcare, Science and society

Eating fish as a child seems to protect you from hay fever

Genetically modified organisms (GMO) - пт, 2018-02-23 12:49
Infants who eat fish are less likely to develop hay fever later on, a finding that suggests changing diets have played a role in rising allergy rates
Категории: Science and society

Eating fish as a child seems to protect you from hay fever

Genetics - пт, 2018-02-23 12:49
Infants who eat fish are less likely to develop hay fever later on, a finding that suggests changing diets have played a role in rising allergy rates
Категории: Biology

Eating fish as a child seems to protect you from hay fever

HIV and AIDS - пт, 2018-02-23 12:49
Infants who eat fish are less likely to develop hay fever later on, a finding that suggests changing diets have played a role in rising allergy rates
Категории: Healthcare, Science and society

Ancient ‘dark-skinned’ Briton Cheddar Man find may not be true

Genetics - пт, 2018-02-23 12:02
The headline was that an ancient Briton from 10,000 years ago had dark skin, but the genetics of skin colour are so complex that we can’t be sure
Категории: Biology

Ancient ‘dark-skinned’ Briton Cheddar Man find may not be true

Genetically modified organisms (GMO) - пт, 2018-02-23 12:02
The headline was that an ancient Briton from 10,000 years ago had dark skin, but the genetics of skin colour are so complex that we can’t be sure
Категории: Science and society

Ancient ‘dark-skinned’ Briton Cheddar Man find may not be true

HIV and AIDS - пт, 2018-02-23 12:02
The headline was that an ancient Briton from 10,000 years ago had dark skin, but the genetics of skin colour are so complex that we can’t be sure
Категории: Healthcare, Science and society

Having children may add 11 years to a woman’s biological age

Genetically modified organisms (GMO) - пт, 2018-02-23 09:00
Having a baby seems to be linked to shorter caps on the ends of a woman’s chromosomes – a sign of ageing that has been linked to disease and a shorter lifespan
Категории: Science and society

Having children may add 11 years to a woman’s biological age

Genetics - пт, 2018-02-23 09:00
Having a baby seems to be linked to shorter caps on the ends of a woman’s chromosomes – a sign of ageing that has been linked to disease and a shorter lifespan
Категории: Biology

Having children may add 11 years to a woman’s biological age

HIV and AIDS - пт, 2018-02-23 09:00
Having a baby seems to be linked to shorter caps on the ends of a woman’s chromosomes – a sign of ageing that has been linked to disease and a shorter lifespan
Категории: Healthcare, Science and society

Effective polyploidy causes phenotypic delay and influences bacterial evolvability

PLOS Biology (new articles) - пт, 2018-02-23 00:00

by Lei Sun, Helen K. Alexander, Balazs Bogos, Daniel J. Kiviet, Martin Ackermann, Sebastian Bonhoeffer

Whether mutations in bacteria exhibit a noticeable delay before expressing their corresponding mutant phenotype was discussed intensively in the 1940s to 1950s, but the discussion eventually waned for lack of supportive evidence and perceived incompatibility with observed mutant distributions in fluctuation tests. Phenotypic delay in bacteria is widely assumed to be negligible, despite the lack of direct evidence. Here, we revisited the question using recombineering to introduce antibiotic resistance mutations into E. coli at defined time points and then tracking expression of the corresponding mutant phenotype over time. Contrary to previous assumptions, we found a substantial median phenotypic delay of three to four generations. We provided evidence that the primary source of this delay is multifork replication causing cells to be effectively polyploid, whereby wild-type gene copies transiently mask the phenotype of recessive mutant gene copies in the same cell. Using modeling and simulation methods, we explored the consequences of effective polyploidy for mutation rate estimation by fluctuation tests and sequencing-based methods. For recessive mutations, despite the substantial phenotypic delay, the per-copy or per-genome mutation rate is accurately estimated. However, the per-cell rate cannot be estimated by existing methods. Finally, with a mathematical model, we showed that effective polyploidy increases the frequency of costly recessive mutations in the standing genetic variation (SGV), and thus their potential contribution to evolutionary adaptation, while drastically reducing the chance that de novo recessive mutations can rescue populations facing a harsh environmental change such as antibiotic treatment. Overall, we have identified phenotypic delay and effective polyploidy as previously overlooked but essential components in bacterial evolvability, including antibiotic resistance evolution.
Категории: Biology, Journals

Reproducibility of preclinical animal research improves with heterogeneity of study samples

PLOS Biology (new articles) - пт, 2018-02-23 00:00

by Bernhard Voelkl, Lucile Vogt, Emily S. Sena, Hanno Würbel

Single-laboratory studies conducted under highly standardized conditions are the gold standard in preclinical animal research. Using simulations based on 440 preclinical studies across 13 different interventions in animal models of stroke, myocardial infarction, and breast cancer, we compared the accuracy of effect size estimates between single-laboratory and multi-laboratory study designs. Single-laboratory studies generally failed to predict effect size accurately, and larger sample sizes rendered effect size estimates even less accurate. By contrast, multi-laboratory designs including as few as 2 to 4 laboratories increased coverage probability by up to 42 percentage points without a need for larger sample sizes. These findings demonstrate that within-study standardization is a major cause of poor reproducibility. More representative study samples are required to improve the external validity and reproducibility of preclinical animal research and to prevent wasting animals and resources for inconclusive research.
Категории: Biology, Journals

Miniature personalised tumours could help you get the best chemo

Genetically modified organisms (GMO) - чт, 2018-02-22 21:00
Growing mini tumours in the lab from a patient’s own cells could help doctors discover the best way to treat each person, homing in on the right drugs to use
Категории: Science and society

Neanderthals made the oldest cave art in the world

Genetically modified organisms (GMO) - чт, 2018-02-22 21:00
We weren’t the only ancient artists – the discovery of 66,700-year-old cave art show our Neanderthal cousins also liked to draw
Категории: Science and society

Miniature personalised tumours could help you get the best chemo

Genetics - чт, 2018-02-22 21:00
Growing mini tumours in the lab from a patient’s own cells could help doctors discover the best way to treat each person, homing in on the right drugs to use
Категории: Biology

Neanderthals made the oldest cave art in the world

Genetics - чт, 2018-02-22 21:00
We weren’t the only ancient artists – the discovery of 66,700-year-old cave art show our Neanderthal cousins also liked to draw
Категории: Biology

Miniature personalised tumours could help you get the best chemo

HIV and AIDS - чт, 2018-02-22 21:00
Growing mini tumours in the lab from a patient’s own cells could help doctors discover the best way to treat each person, homing in on the right drugs to use
Категории: Healthcare, Science and society

Neanderthals made the oldest cave art in the world

HIV and AIDS - чт, 2018-02-22 21:00
We weren’t the only ancient artists – the discovery of 66,700-year-old cave art show our Neanderthal cousins also liked to draw
Категории: Healthcare, Science and society