Abstract
The effective population size (Ne) under marker-assisted selection (MAS) was considered in terms of the intrafamily (intraclass) correlation of selection criterion. It was shown that the effect of MAS on Ne depends not only on the phenotypic correlation (t) among family members but also on the genetic relationship (r) among family members. MAS with individual's phenotype and molecular score reduces Ne when t < r , and increases Ne when t > r , compared to the conventional selection on individual's phenotype alone. ln contrast, compared to the selection with phenotypic information from individual and family members, MAS using phenotypic and molecular information from individual and family members is expected to increase Ne when t < r , and has the reversed effect when t > r . Assuming a population consisting of full-sib families (r = 1⁄2), numerical computation and Monte Carlo simuation were carried out to illustrate and check the result.
