On the number of reproductives contributing to a half-sib progeny array

We address various statistical aspects of biological parentage in multi-off spring broods that arise via multiple paternity or multiple maternity and, hence, consist of mixtures of full- and half-sibs. Conditioned on populatio n genetic parameters, computer simulations described herein permit estimati on of: (1) the mean number of offspring needed to detect all parental gamet es in a brood and (2) the relationship between the number of distinct paren tal gametes found in a brood and the number of parents. Results are relevan t to the design of empirical studies employing molecular markers to assess genetic parentage in polygynous or polyandrous species with large broods, s uch as are found in many fishes, amphibians, insects, plants and other grou ps. The utility of this approach is illustrated using two empirical data se ts.