David G King

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Simple sequence repeats (SSRs) often serve to modify genes with which they are associated. The influence of SSRs on gene regulation, transcription and protein function typically depends on the number of repeats, while mutations that add or subtract repeat units are both frequent and reversible. SSRs thus provide a prolific source of quantitative and(More)
Analyses of complete cytochrome b sequences from all species of cranes (Aves: Gruidae) reveal aspects of sequence evolution in the early stages of divergence. These DNA sequences are > or = 89% identical, but expected departures from random substitution are evident. Silent, third-position pyrimidine transitions are the dominant substitution type, with(More)
Activity in the flight muscles and jump muscles in Drosophila can be stimulated by excitation of a pair of giant fibres that enter the thoracic ganglion from the brain. Contrary to previous descriptions, these giant fibres are not themselves motor axons. Each giant fibre contacts both a large motor axon and an interneuron. The motor axon innervates the(More)
Most traits in biological populations appear to be under stabilizing selection, which acts to eliminate quantitative genetic variation. Yet, virtually all measured traits in biological populations continue to show significant quantitative genetic variation. The paradox can be resolved by postulating the existence of an abundant, though unspecified, source(More)
Simple sequence repeats (SSRs), sometimes described as genetic 'stutters,' are DNA tracts in which a short base-pair motif is repeated several to many times in tandem (e.g. CAGCAGCAG). These sequences experience frequent mutations that alter the number of repeats. Because SSRs are commonly located in promoters, untranslated regions and even coding(More)
The stomatogastric ganglion of the lobster consists of about thiry neurons, mainly large monopolar cells, which have been well characterized physiologically. This paper presents an anatomical description of this ganglion, emphasizing synaptic connections in the neuropil. The neuron cell bodies are located on the dorsal surface of the ganglion. They send(More)
ki ctes over whether molecular sequence data should be partitioned for phylogenetic analysis often confound two types of heterogeneity among partitions. We distinguish historical heterogeneity (i.e., different partitions have different evolutionary relationships) from dynamic heterogeneity (i.e., different partitions show different patterns of sequence(More)
The peritrophic membrane of Drosophila melanogaster consists of four layers, each associated with a specific region of the folded epithelial lining of the cardia. The epithelium is adapted to produce this multilaminar peritrophic membrane by bringing together several regions of foregut and midgut, each characterized by a distinctively differentiated cell(More)
Identified neurons in the stomatogastric ganglion of the lobster were examined and reconstructed by serial section electron microscopy. Each motor neuron consists of a soma, a primary process leading directly from the soma to the motor axon which leaves the ganglion, and a group of secondary processes which branch from the primary process and ramify within(More)
Staphylococcus aureus pathogenicity islands (SaPIs) are mobile elements that are induced by a helper bacteriophage to excise and replicate and to be encapsidated in phage-like particles smaller than those of the helper, leading to high-frequency transfer. SaPI mobilization is helper phage specific; only certain SaPIs can be mobilized by a particular helper(More)