Insights into vertebrate evolution from the chicken genome sequence

The chicken has recently joined the ever-growing list of fully sequenced animal genomes. Its unique features include expanded gene families involved in egg and feather production as well as more surprising large families, such as those for olfactory receptors. Comparisons with other vertebrate genomes move us closer to defining a set of essential vertebrate genes

Becoming a teacher: conceptual and practice development in the learning and skills sector

Drawing on a mixed-methods study of in-service learning and skills sector (LSS) trainees, comprising beginning- and end-of-year surveys and six longitudinal case studies together with literature on trainees’ development in the LSS, schools and higher education sectors, conceptual and practice development continua are proposed. Conceptions become more multi-dimensional and increasingly link teaching and learning whilst initial concern with the practicalities of teaching is followed by recognition of learners’ needs. Next, greater emphasis is placed on learner autonomy and catering for individuals’ needs and finally assessment and evaluation is used systematically to shape practice. The continua offer an understanding of the subtleties and complexities of trainee development allowing for different starting and end points and accommodating varied work contexts. I argue that this provides a more adequate basis for the development of initial teacher education (ITE) than the prescriptive approach embedded within recent LSS ITE policy reforms

Hsp70 sequences indicate that choanoflagellates are closely related to animals

AbstractOver 130 years ago, James-Clark [1, 2] noted a remarkable structural similarity between the feeding cells of sponges (choanocytes) and a group of free-living protists, the choanoflagellates. Both cell types possess a single flagellum surrounded by a collar of fine tentacles [3]. The similarity led to the hypothesis that sponges, and, by implication, other animals, evolved from choanoflagellate-like ancestors. Phylogenetic analysis of ribosomal DNA neither supports nor refutes this hypothesis [4–6]. Here, we report the sequence of an hsp70 gene and pseudogene from the freshwater choanoflagellate Monosiga ovata. These represent the first nuclear-encoded protein-coding sequences reported for any choanoflagellate. We find that Monosiga and most bilaterian hsp70 genes have high GC contents that may distort phylogenetic tree construction; therefore, protein sequences were used for phylogenetic reconstruction. Our analyses indicate that Monosiga is more closely related to animals than to fungi. We infer that animals and at least some choanoflagellates are part of a clade that excludes the fungi. This is consistent with the origin of animals from a choanoflagellate-like ancestor