Alternative splicing types observed in five most studied species.

ES – exon skipping; IR – intron retention; A3 – alternative 3′ splice site; A5 – alternative 5′ splice site; ME – mutually exclusive exons; N – number of alternatively spliced genes; A – alternative splicing ratio (proportion of alternatively spliced genes); R – ratio of the total number of protein products to the total number of protein genes; H – Shannon's index; Hmax – maximum possible value of Shannon's index, where for a given n, H is a maximum and equal to logn, when all the Pi are equal (i.e., 1/n);E – Shannon's equitability (E = H/Hmax). Complex cases are denoted as combinations of these abbreviations. Pr - proportion (ratio) of the type to all types.