Genotype analysis failed for two participants, yielding 248 samples for association analysis.
Required sample sizes for association studies for a single allele and for GWAS are shown in the Tables 6 and 7, respectively.
However it is not possible in this case to ascribe this association to the same haplotype identified by Carlton et al. (haplotype 6).[9] These data were unable to be combined with that of Wesoly et al [11]; however, in their sample P for association of haplotype 6 with RA was 0.48 (frequency of 10.7% in cases, 11.9% in controls).
With greater sample sizes for association studies and more loci available for fitting, one may be able to reliably fit statistical distributions with more free parameters, for example the gamma distribution (which is very flexible) with free shape and rate parameters.
Thus, for the foreseeable future, genotype imputation is likely to remain an efficient and cost-effective means of inferring genotypes and increasing sample sizes for association studies.
Quality-control assessment of genotypes, including sample completion and SNP call rates, concordance rates, deviation from fitness for the Hardy Weinberg proportions in control DNA and final sample selection for association analyses, are described elsewhere (26– 26).
Another problem of using phenotypic value is that the systematic environmental effects on measured phenotypes may not be efficiently corrected because the sample size for association study is usually relative small in comparison with that for EBV prediction.
One participant from each duplicate pair (π > 0.95) or relative pair (0.4 ≤ π ≤ 0.95) was included in the unrelated sample used for association analyses, prioritizing based on nonmissing disease status and/or covariates and then higher SNP call rate.
To avoid this, it might be beneficial (if possible) to ensure an even distribution of trait values within and between subpopulations in the plant genotype sample employed for association analysis.
Case control sample for genetic association with type 2 diabetes As a control sample we used all participants with normal glucose tolerance from the above-mentioned sample (n = 2,041).
