Scanning electron micrographs of clots made from fibrinogen γ-chain splice variants. Clots were made from purified fibrinogen γ-chain splice variants and observed by scanning electron microscopy. Scale bars indicate 2 μm. There is a marked difference in fiber size and density of clot, with thinner fibers and smaller pores for clots made from γA/γ′ fibrinogen (A) compared with the more frequent variant γA/γA (B). Unfractionated fibrinogen (C) produces clots with an appearance that is more similar to that of γA/γA.