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Toxic Microcystis strains often produce several isoforms of the cyclic hepatotoxin microcystin, and more than 65 isoforms are known. This has been attributed to relaxed substrate specificity of the adenylation domain. Our results show that in addition to this, variability is also caused by genetic variation in the microcystin synthetase genes. Genetic(More)
Attentional functioning in mice was assessed in an analogue of the five-choice serial reaction time task in which the requirement was to detect brief visual stimuli presented across five spatial locations. Two hybrid strains of mice were assessed; F1 C57Bl/6xDBA/2 and C57Bl/6x129sv. Both strains acquired the task to high levels of performance with, in(More)
A new timescale has recently been established for human mitochondrial DNA (mtDNA) lineages, making mtDNA at present the most informative genetic marker system for studying European prehistory. Here, we review the new chronology and compare mtDNA with Y-chromosome patterns, in order to summarize what we have learnt from archaeogenetics concerning five(More)
In a small fraction of mammalian genes--at present estimated at less than 1% of the total--one of the two alleles that is inherited by the offspring is partially or completely switched off. The decision as to which one is silenced depends on which allele was inherited from the mother and which from the father. These idiosyncratic loci are known as imprinted(More)
Imprinted genes show differential expression between maternal and paternal alleles as a consequence of epigenetic modification that can result in 'parent-of-origin' effects on phenotypic traits. There is increasing evidence from mouse and human studies that imprinted genes may influence behavior and cognitive functioning. Previous work in girls with Turner(More)
In normal mammals, autosomal genes are present in duplicate (i.e. two alleles), one inherited from the father, and one from the mother. For the majority of genes both alleles are transcribed (or expressed) equally. However, for a small subset of genes, known as imprinted genes, only one allele is expressed in a parent-of-origin dependent manner (note that(More)
BACKGROUND Attention-deficit/hyperactivity disorder (ADHD) is a complex neurodevelopmental disorder characterized by deficits in attention, increased motor impulsivity, and hyperactivity. Preliminary work in mice and humans has suggested the X-linked gene STS (which encodes the enzyme steroid sulfatase) as a mediator of attentional functioning and as a(More)
As evidence for the existence of brain-expressed imprinted genes accumulates, we need to address exactly what they are doing in this tissue, especially in terms of organisational themes and the major challenges posed by reconciling imprinted gene action in brain with current evolutionary theories attempting to explain the origin and maintenance of genomic(More)
BACKGROUND The loss of all, or part of an X chromosome, in Turner syndrome (TS, 45,XO) results in deficits in attentional functioning. METHODS Using a 39,XO mouse model, we tested the hypothesis that X-monosomy and/or parental origin of the single X chromosome may influence visuospatial attentional functioning in a 5-choice serial reaction time task(More)
A link between climate change and human evolution during the Pleistocene has often been assumed but rarely tested. At the macro-evolutionary level Foley showed for hominids that extinction, rather than speciation, correlates with environmental change as recorded in the deep sea record. Our aim is to examine this finding at a smaller scale and with(More)