21 research outputs found

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

    Shear Wave Splitting and Mantle Anisotropy: Measurements, Interpretations, and New Directions

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    The Role of Myosin II Motor Activity in Distributing Myosin Asymmetrically and Coupling Protrusive Activity to Cell Translocation

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    Nonmuscle myosin IIA and IIB distribute preferentially toward opposite ends of migrating endothelial cells. To understand the mechanism and function of this behavior, myosin II was examined in cells treated with the motor inhibitor, blebbistatin. Blebbistatin at ≥30 μM inhibited anterior redistribution of myosin IIA, with 100 μM blebbistatin causing posterior accumulation. Posterior accumulation of myosin IIB was unaffected. Time-lapse cinemicrography showed myosin IIA entering lamellipodia shortly after their formation, but failing to move into lamellipodia in blebbistatin. Thus, myosin II requires motor activity to move forward onto F-actin in protrusions. However, this movement is inhibited by myosin filament assembly, because whole myosin was delayed relative to a tailless fragment. Inhibiting myosin's forward movement reduced coupling between protrusive activity and translocation of the cell body: In untreated cells, body movement followed advancing lamellipodia, whereas blebbistatin-treated cells extended protrusions without displacement of the body or with a longer delay before movement. Anterior cytoplasm of blebbistatin-treated cells contained disorganized bundles of parallel microfilaments, but anterior F-actin bundles in untreated cells were mostly oriented perpendicular to movement. Myosin II may ordinarily move anteriorly on actin filaments and pull crossed filaments into antiparallel bundles, with the resulting realignment pulling the cell body forward
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