A model for estimating the extent of variegation in mosaic tissues

A method is described which allows the size of patches of like cells in mosaic tissues to be estimated from the frequency with which small samples taken from the tissue contain both of the mosaic cell types. The mosaic patches are represented as close-packed geometric figures arranged in twoor three-dimensional tissues. Small samples drawn at random from these tissues will include portions of one or more patches; only those samples which include portions of two or more dissimilar patches (mixed samples) will contain both cell types. The expected frequency of mixed samples is calculated as a function of the shape of the mosaic patches, the frequency of the two mosaic cell types and the sample to patch size ratio. This expected frequency is not strongly dependent on patch shape for triangular, square and hexagonal patches in two dimensions or for cubic and orthotetrakaidekahedral patches in three dimensions. Elongation of square patches along one axis or of cubic patches along one or two axes results in slight increases in the expected frequency of mixed samples for given sample to patch size ratio.