Nucleotide-free structures of KIF20A illuminate atypical mechanochemistry in this kinesin-6

KIF20A is a critical kinesin for cell division and a promising anti-cancer drug target. The mechanisms underlying its cellular roles remain elusive. Interestingly, unusual coupling between the nucleotide- and microtubule-binding sites of this kinesin-6 has been reported, but little is known about how its divergent sequence leads to atypical motility properties. We present here the first high-resolution structure of its motor domain that delineates the highly unusual structural features of this motor, including a long L6 insertion that integrates into the core of the motor domain and that drastically affects allostery and ATPase activity. Together with the high-resolution cryo-electron microscopy microtubule-bound KIF20A structure that reveals the microtubule-binding interface, we dissect the peculiarities of the KIF20A sequence that influence its mechanochemistry, leading to low motility compared to other kinesins. Structural and functional insights from the KIF20A pre-power stroke conformation highlight the role of extended insertions in shaping the motor's mechanochemical cycle. Essential for force production and processivity is the length of the neck linker in kinesins. We highlight here the role of the sequence preceding the neck linker in controlling its backward docking and show that a neck linker four times longer than that in kinesin-1 is required for the activity of this motor

Sympatric divergence and clinal variation in multiple coloration traits of Ficedula flycatchers

Geographic variation in phenotypes plays a key role in fundamental evolutionary processes such as local adaptation, population differentiation and speciation, but the selective forces behind it are rarely known. We found support for the hypothesis that geographic variation in plumage traits of the pied flycatcher Ficedula hypoleuca is explained by character displacement with the collared flycatcher Ficedula albicollis in the contact zone. The plumage traits of the pied flycatcher differed strongly from the more conspicuous collared flycatcher in a sympatric area but increased in conspicuousness with increasing distance to there. Phenotypic differentiation (P-ST) was higher than that in neutral genetic markers (F-ST), and the effect of geographic distance remained when statistically controlling for neutral genetic differentiation. This suggests that a cline created by character displacement and gene flow explains phenotypic variation across the distribution of this species. The different plumage traits of the pied flycatcher are strongly to moderately correlated, indicating that they evolve non-independently from each other. The flycatchers provide an example of plumage patterns diverging in two species that differ in several aspects of appearance. The divergence in sympatry and convergence in allopatry in these birds provide a possibility to study the evolutionary mechanisms behind the highly divergent avian plumage patterns

Who was that? Enriched eReading through in-book visualisation

The shift to electronic books has opened a realm of possibilities for assisting users in reading books, but little of this potential has been realised. Today’s eReaders offer simple search features but rarely make any ongoing supportive data about a book’s content available. We investigated the use of visual aids for eBook reading and developed an eReader prototype. Our prototype provides a timeline of character appearances throughout a book, coupled with interactive identifications and lists of characters as they appear within the narrative. We present results of a user study in which we observe that contextually-relevant information can enhance a reader’s experience

Data from: Candidate genes for colour and vision exhibit signals of selection across the pied flycatcher (Ficedula hypoleuca) breeding range

The role of natural selection in shaping adaptive trait differentiation in natural populations has long been recognized. Determining its molecular basis, however, remains a challenge. Here, we search for signals of selection in candidate genes for colour and its perception in a passerine bird. Pied flycatcher plumage varies geographically in both its structural and pigment-based properties. Both characteristics appear to be shaped by selection. A single-locus outlier test revealed two of fourteen loci to exhibit significantly elevated signals of divergence. The first of these, the follistatin gene, is expressed in the developing feather bud and found in pathways with genes that determine the structure of feathers and may thus be important in generating variation in structural colouration. The second is a gene potentially underlying the ability to detect this variation: SWS1 opsin. These two loci were most differentiated in two Spanish pied flycatcher populations, which are also among the populations that have the highest ultraviolet reflectance. The follistatin and SWS1 opsin genes, thus provide strong candidates for future investigations on the molecular basis of adaptively significant traits and their co-evolution. The data package contains two datasets: - The SNP genotypes of the pied flycatcher individuals utilised in this study by population. Data have been collected in the field and the genotypes subsequently generated in a genetics laboratory. The loci are listed at the start of the page, in the order that they presented in in the file (left to right).The alleles are in 2-digit format, one column per locus. Z-linked loci are denoted with a Z and haplotypes denoted with the abbreviaiton 'hap'. Population names correspond to the sampling site of the individual (e.g. Jeseniky = Jeseniky Mountains, the Czech Republic) as presented in Table 1 of the publication. - The microsatellite genotypes for the pied flycatchers collected from Dartmoor, which have not previously been published elsewhere. Data have been collected in the field and the genotypes subsequently generated in a genetics laboratory. The alleles are in 2-digit format, one column per locus. The loci are listed at the start of the page, in the order that they presented in in the file (left to right). The microsatellite data for the other populations is the same as that presented in Lehtonen et al. 2009 Molecular Ecology 18:4463-447