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.
African genomes illustrate population histories
We now know far more about the patterns of genetic diversity in the most genetically diverse of all continents thanks to the new publication of the African Genome Variation Project. This international project took in genotypes from 1481 individuals and whole genome sequences from 320 more, originating from 18 ethno-linguistic groups across sub-Saharan Africa, from the Amhara to the Zulu. The project found relatively modest degrees of differentiation between the populations, which is consistent with the ‘Bantu expansion’ – a population expansion from West Africa that occurred 3000 to 5000 years ago. There are also signs of complex admixture of multiple hunter gatherer and Eurasian populations. These data illustrate how best to design efficient medical genomic studies for African populations in the future.
Deepti Gurdasani et al. Nature
Signalling proteins: many arrangements work
The evolution of signalling networks shows remarkable reuse of separate protein domains, and comparative genomics suggests that rearrangement of these domains into new modular structures has a prominent role in the evolution of networks. A new study which investigates the mating pheromone response pathway in yeast adds some support to the idea. It shows that when some degree of domain rearrangement occurs, activation of the pathway appears normal, at comparable levels to wild-type proteins. The authors suggest that some parts of the signalling complex have interchangeable roles, and that signalling complexes may not have a tight spatial structure: instead, they could represent a loose association of proteins and their domains. Whatever the reason, the ease with which domain rearrangement can apparently be accommodated backs up the idea that it could generate a large pool of raw diversity for evolution to work on.
Sato et al. PLOS Biology
Size matters
Throughout the animal kingdom males vary in the size and speed of their sperm. It is assumed that this variation has evolutionary significance; that is, in the many species where females mate with multiple males, having longer and faster sperm will result in males fathering more offspring. Experimental support for this idea is surprisingly limited, but new research on zebra finches supports this hypothesis. Sperm samples were taken from male birds, who were then classed as having long or short sperm. Females were consecutively mated with one male with long sperm and another male with short sperm. Following mating, the ova of the females were examined. Longer sperm reached the ova in larger numbers than smaller sperm and this resulted in males with long sperm siring a larger proportion of the embryos. At least for zebra finches, it seems size does indeed matter for males when it comes to fathering children.
Bennison et al. Proceedings of the Royal Society B
Send us your skeletons
Data on fish populations is crucial to inform the (often fierce) debates around conservation of fishing stocks. However collecting the required data using traditional sampling techniques can be difficult given limited funds. The use of ‘citizen scientists’ to provide data has been suggested as a way to overcome these difficulties, but is an approach with both promise and pitfalls. A new study assesses the impact of one such initiative on assessments of stocks of three commercially important fish species on the western coast of Australia. Dubbed ‘Send us your skeletons’, the programme encourages recreational fishers to send their fish skeletons to the local Department of Fisheries to use as data in sampling efforts. In its first three years, the program has resulted in a substantial increase in the number of biological samples collected, in a cost-effective way. A common concern when estimating fish numbers using this approach is that recreational fisherman tend to keep the biggest fish they catch, thus potentially skewing the data on size distributions in a population. However this study suggests that the increase in the number of samples being donated largely overcame this issue. The ‘Send us Your Skeletons’ project suggests that citizen science has the potential to make a big contribution to wildlife conservation efforts.
Fairclough et al. Scientific Reports
Algae within algae
The story of the origins of the photosynthetic machinery in eukaryotes is well known – cyanobacterial lodgers moved into eukaryotic cells and liked it so much they stayed, becoming photosynthetic plastids. However things are not so simple in all photosynthetic organisms: the photosynthetic organelles in Chromist algae in particular have a complex history. A new study claims to have resolved this problem using phylogenetic methods – these needed novel statistical techniques to account for genes that were transferred from the endosymbiont genome. Rather than the single endosymobiosis that occurred in other eukaryotes, chromist photosynthesis arose through a series of such events. Initially a red alga was adopted by a cryptophyte, then this organism by an ochrophyte, and finally this by a haptophyte, like a series of Russian dolls.
John W Still et al. Nature Communications
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.