Open Reading Frame brings together a selection of recent publication highlights from elsewhere in the open access ecosystem. This week we take a look at the past few weeks in biology.
Are noisy boats catching up with the sea hare?
A number of studies in recent years have suggested that noise caused by humans has detrimental effects on animals. Most of these studies focus on birds and mammals; but what about invertebrates, which intuitively one would not expect to be so affected by our noise? Researchers tested the effect of man-made noise on eggs of the sea hare, a marine mollusc, found off the coast of a Polynesian island. In a semi-natural experiment, some eggs were exposed to pre-recorded motor-boat noises from underwater speakers. The development of these eggs and the resulting young was compared to eggs from the same mothers not exposed to boat noise. More eggs in the noisy group failed to develop and, of those eggs that hatched, more of the young died when exposed to the motor-boat recordings. Sea hare eggs will of course naturally be exposed to a considerable amount of noise from passing boats; the researchers suggest this could have a significant negative impact on this ecologically important species, who are specialist grazers on blooms of the toxic cyanobacterium, L. Majuscule.
Nedelec et al. Scientific Reports
Pre-historic farming in the extremes
Four and a half thousand years ago, farming had spread across much of Europe and Asia. However, it has been thought unlikely that farming was possible at this time in the northern areas of the continent, with their unsuitable cold climates. New research however suggests domestication of animals had taken place at this time in South West Finland, on the same northern latitude as Alaska and Greenland. Gathering evidence about the lifestyles of early people in this region has been difficult as animal bones do not preserve well in the acidic Finnish soil. Researchers overcame this problem by analysing organic residues found on pottery fragments. Isotopes found strongly suggested that people used these pots to store animal milk, the first clear evidence of animal domestication from such a northern climate during pre-historic times. Tentative evidence was also found that these farming habits were later temporarily lost. It is possible that during episodes where the climate deteriorated people were unable to continue farming and had to revert back to an exclusive hunter-gatherer lifestyle to survive; a reminder of how fragile early farming would have been in such extreme locations.
Cramp et al. Proceedings of the Royal Society B
Egg-lighting new results
Bird eggs differ greatly between species in many of their physical characteristics, including those that may affect how much light can pass through them. It is also known that differences in lighting of eggs can influence the developing chick. However, it isn’t clear whether the differences between shell features are linked to the light environment in which eggs are incubated in wild birds. In this comparative study, eggs from 74 species of British breeding birds were examined for the amount and wavelengths of light that pass through their eggshells, along with physical factors such as shell thickness, water permeability, colour and amount of pigmentation.
Predictably, less light passes through thicker and more pigmented shells. However, there is no link between water permeability and light transmission despite this being related to the number of pores in shells. The eggs of birds that nest in hollows, burrows or other shaded areas – that are typically pure white or pale blue – transmit more light than those laid in open nests. The authors suggest that this may be a response of birds to aid the development of their chicks under low light conditions. They also note that the eggs of species with longer incubations were better at blocking UV light, which they suggest may be an adaptation to prevent harmful UV radiation from damaging embryonic development during their longer light exposure.
Maurer et al. Functional Ecology
Cellular cycles in synchrony
Just as whole organisms have daily (circadian) rhythms, so can individual cells. Cells also display another cyclical series of cellular events – the cell cycle – that controls cell duplication. It has been observed before that these two cycles can be coupled. The mechanisms of how the cell cycle is controlled by circadian rhythms has also previously been investigated. In this latest study time-lapse imaging of mouse fibroblast cells is used to track thousands of individual cell cycle and circadian rhythms, finding that the two are tightly synchronised – even in the face of greatly different growth, drug and genetic conditions that might have been expected to disrupt this linkage. Mathematical modelling of the interacting systems revealed that it is the cell cycle that has a dominant influence over the circadian cycle, resulting in the robust synchronization.
Bieler et al. Molecular Systems Biology
One of the ways that different species are maintained despite individuals living and breeding the same places are barriers to reproduction, which can either be ‘pre-zygotic’ (behavioural or physical differences that mean a zygote is never formed) or ‘post-zygotic’ (genetic incompatibilities that mean zygotes do not develop into fertile adults). A new study in nematodes reveals the ultimate pre-zygotic barrier: if you mate with other species, you die. This dramatic result is brought about by the evolutionary arms race between males and females within each species. As for many organisms, there are an ever-evolving set of sexual features that represent the conflict between males’ desire for fecundity and females’ (in worms, these are often actually hermaphrodites) desire to be choosy about their mates. In the case of these nematodes, the particular feature is invasive sperm, which aggressively migrate within the female to ensure fertilisation. While females of the same species may be equipped to deal with this, those unlucky females from other species have sperm invade critical parts of the body, leading to infertility and sometimes a gruesome death.
Ting et al, PLOS Biology
Of mice and men?
Animal models are a key part of biomedical research, but their usefulness largely depends on how well they mimic the mechanisms of human disease. A paper just published in PNAS claims that for inflammatory disease, they are good models – but this directly conflicts with a previous paper published in the same journal just last year suggesting that they did poorly in this context. These sorts of scientific disagreements aren’t so strange, you might think, particularly on issues of such fundamental importance. Actually, this one is. Both papers are based on exactly the same set of gene expression data, so how did they reach such different conclusions?
The answer lies in the choices made during data analysis, and whether one compares genes whose expression changes in mice, humans or both. A reminder, perhaps, in the big data era, that data isn’t the only thing that matters: it’s what you do with it that counts.
Takaoa and Miyakawa, PNAS
Written by Christopher Foote, Executive Editor for the BMC Series, Kester Jarvis (@Kestererer), Senior Editor for BMC Biology, and Tim Sands, Executive Editor for the BMC Series.