The genetic analysis of family structured inbreeding depression studies.

An important question emerging from theoretical studies of mating system evolution is whether the fitness of a randomly extracted, fully inbred genotype will exceed the mean of outbred individuals. We introduce two statistics (I(1) and I(2)) related to the probability of extracting a high line. I(1) and I(2) can be estimated from the family structured experimental designs typically used to estimate inbreeding depression (ID). Maximum likelihood procedures are developed from an explicit genetic model. These yield parameter estimates and provide the likelihoods necessary to test hypotheses, for example, whether population-level ID is nonzero. Finally, we describe a new publicly available computer program titled 'IDG' (Inbreeding Depression Genetics) to execute these procedures.