How dissimilar are the fingerprints of identical twins?

Question

It is a very well-known fact, stated multiple times even in this Stack Exchange, that identical twins have different fingerprints. However, to what specific extents, and in what specific ways, do the sets of fingerprints of identical twins typically differ? Are the differences usually very minor (e.g., just a few stray loops and whorls here and there)? Are they perceptibly different but still fairly similar, with the similarities most likely stemming from heredity and/or cultural ties? Or does the determination of fingerprint patterns behave similarly to a uniformly weighted random number generator, with the fingerprint sets of twins being just as different as those of two people born on opposite sides of the world?

Obviously, due to the random/probabilistic nature of this feature, there may be no single answer to this question — there may be cases where one pair of twins has fingerprints that are more similar than those of another pair. But does anyone know what typical similarities and differences are present between the fingerprint sets of identical twins, and, if possible, the biological causes of such similarities and differences?

Answer 1

Identical twin fingerprints are different, but generally more similar than to random people. For example:

Fingerprint recognition with identical twins is a challenging task due to the closest genetics-based relationship existing in the identical twins ... Srihari et al. [6] analyzed the similarity between twins' fingerprints in a study using fingerprint images from 298 pairs of twins. The authors analyzed this similarity using two-level features. With the features of level 1, they found that twins' fingers are much more likely (55%) to have the same pattern type than non-twins' fingers (32%). With the features of level 2, they concluded that the similarity between the fingerprints from twin fingers is higher than from two arbitrary fingers.

Fingerprint Recognition with Identical Twin Fingerprints

Dermatoglyphic asymmetry and diversity traits from a large number of twins (MZ and DZ) were analyzed based on principal factors to evaluate genetic effects and common familial environmental influences on twin data by the use of maximum likelihood-based Variance decomposition analysis. ... The present results are similar with the earlier results of finger ridge count diversity in twin data, which suggested that finger ridge count diversity is under genetic control.

--Inheritance of dermatoglyphic asymmetry and diversity traits in twins based on factor: variance decomposition analysis