W2Image forensicsWestern BlotLayer 1 (Deterministic)

Band Morphology

Examines the shape of protein bands. A real band is irregular, with ragged edges, an asymmetric profile, and a size that varies from lane to lane with protein amount. A band that is unnaturally smooth, circular, convex, and identical to its neighbours in shape and size points to generation or cloning rather than measurement.

Technical description

Detects bands and computes three contour descriptors each: circularity (4*pi*area/perimeter^2), convexity (area/hull_area), and edge smoothness (hull_perimeter/perimeter). It aggregates the mean circularity and smoothness and the coefficient of variation of the circularities and of the band areas. Artificial signals accumulate from high circularity (above 0.60 and 0.75), high smoothness (above 0.85 and 0.92), a circularity CV below 0.10, and a band-area CV below 0.10 (identical sizes are unnatural since lanes carry different amounts). The summed signals are scaled to a score capped at 5.0.

How it works

Layer 1 (deterministic): detects bands, computes per-band circularity, convexity, and edge smoothness, then accumulates artificial-morphology signals from high mean circularity, high mean smoothness, low shape variation (circularity CV below 0.10), and low size variation (band-area CV below 0.10). The summed signals scale to a score capped at 5.0; bands with high circularity or smoothness become findings with locations.

Why this matters

Band morphology is a fingerprint of how a band was made. A real band is the smeared, diffuse trace of migrating protein, so its shape is irregular and its size reflects the loaded amount and varies across lanes; a clean, uniform band did not pass through a gel. Ethical image guidance warns that bands must not be beautified into idealised shapes, and fabricated blots frequently reuse a single band, making bands identical in shape and size. Combining how perfect each band is with how alike the bands are separates natural electrophoresis from generation and cloning.

Score thresholds

0-1: Bands have the irregular, variable morphology of real electrophoresis
2-3: Some bands are unusually smooth or circular, or the bands are somewhat uniform
4-5: Bands are smooth, circular, and uniform in shape and size, consistent with generated or cloned bands

Limitations

Shape analysis depends on clean band detection, so faint, smeared, or touching bands can be merged or missed. Circularity from a digital contour is biased by boundary staircasing and can be lowered for small bands. The edge-smoothness measure reads boundary convexity rather than fine edge texture, so a solid band with a clean outline reads as smooth even when genuine, which is why no single descriptor decides the score. The uniformity signals require more than one band and can trip on a genuine blot with similar bands. Band-to-band duplication by pixel content is indicator W1, and background fabrication is indicators W3 and W4; W2 stays on the shape and uniformity of the bands.