The genus Phaseolus (Fabaceae) consists of some 50 species, all of which are distributed in the Americas. Four of these contain cultigens. P. vulgaris (common bean), P. lunatus (lima bean), P. acutifolius (tepary bean), P. coccineus subsp. coccineus (runner bean); and P. coccineus subsp, polyanthus (no English vernacular name). Biochemical markers--phaseolin seed storage protein and isozymes--h...

If one goes backward in time, the number of ancestors of an individual doubles at each generation. This exponential growth very quickly exceeds the population size, when this size is finite. As a consequence, the ancestors of a given individual cannot be all different and most remote ancestors are repeated many times in any genealogical tree. The statistical properties of these repetitions in g...