Assumptions made in modeling the transmission of QTL in this experiment include diploid Mendelian inheritance and negligible natural selection or genetic drift during the process of

random mating and selfing.

For a given gene frequency, the degree of the downward bias is partly dependent on the sampling of different subdivisions and individuals within subdivisions For balanced data from r

random mating populations of size n (i.e., one-level hierarchy), the expected bias of estimated intraclass correlation [Mathematical Expression Omitted] is approximated by (cf.

The indices in "L-S" comparison confirm

random mating and equal performance between sexes and strains thereby ruling out incompatibility issues resulting from effects of radiation treatment.

Parameters of inbreeding analysis in all animals in percent (%) Breed CLA CLWd CLWs DC PN Proportion of inbred Animals 57.5 57.9 54.1 46.9 25.1 Sires 53.8 56.7 55.2 44.1 7.4 Dams 74.4 78.7 74.9 62.6 24.1 Average inbreeding 2.7 1.4 2.5 3.6 1.3 Average co-ancestry 3.1 1.6 3.3 4.2 3.3 Average increase of inbreeding 0.17 0.18 0.56 0.53 -0.08 Average rate of co-ancestry 0.21 0.29 0.56 -0.14 0.29 Expected inbreeding 2.67 1.27 2.65 3.20 1.74 Deviation from

random mating -0.02 0.11 -0.11 0.28 -0.44 CLA, Czech Landrace; CLWd, Czech Large White dam line; CLWs, Czech Large White sire line; DC, Duroc; PN, Pietrain.

For CY and CL, the actual average inbreeding coefficient tended to be smaller than expected inbreeding coefficient based on

random mating since 2004 (Figure 5).

We depart from the assumption that choice is not present, and deviations from

random mating are entirely due to mating propensities.

Selection due to competition acts on the distribution [p.sub.t](z) before

random mating in each generation.

In general, the variance of progeny number among parents should be larger than that expected under

random mating; and together with the degree of relatedness between the mates, the difference of allele frequency between male and female parents generated by genetic drift affect genotype frequencies in the offspring population (Robertson, 1965; Wang, 1996).

Because Ruiz and Barbadilla (1995) statistical approach assumes a

random mating population, exact Hardy-Weinberg tests were performed for each sex (Rousset and Raymond 1995).

For a large population under

random mating, linkage equilibrium can be assumed for all possible pairs of loci, with the result that a similar number of coupling and repulsion combinations occur.

This allows the use of Fisher's (1941) concepts of average effect of an allele substitution and average excess, which are equivalent and easily defined under

random mating. With

random mating, the expected response to selection can be expressed in terms of either of these concepts and the covariance among siblings or between parent and offspring can be used to estimate the additive genetic variance and the heritability of a trait (Kempthorne 1969).

Casady, Kansas State University, that had undergone

random mating and selection for at least 3 cycles before 1984.