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Revision as of 11:34, 14 April 2014
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* If --makeResiduals is used for adjusting covariates, then individuals with missing covariates will also be excluded.
* If --makeResiduals is used for adjusting covariates, then individuals with missing covariates will also be excluded.
* Individuals that are not genotyped will also be excluded from analyses.
* Individuals that are not genotyped will also be excluded from analyses.
* Missing genotypes are imputed using mean genotype of a variant.
== Analyzing Chromosome X==
== Analyzing Chromosome X==
* Special cares only needs
* --xStart and --xEnd options described the start and end position of nonPAR region on chromosome X. The default values are 2699520 and 154931044, according to Human Genome build 19.
* When samples are analyzed as unrelated (no any kind of kinship is used for linear mixed model approach), no special actions needed for analyzing markers on chromosome X.
* If you want to use a linear mixed model approach to correct family structure, population structure, or cryptic relatedness, you should issue --vcX option in your command line. This approach will fit a separate linear mixed model using both autosomal kinship matrix and chromosomeX kinship matrix. This approach is believed to have larger power with type I error well controlled.
* On the other hand, if you want a fast association for chromosome X, another valid approach is to issue --vcX --separateX options. This will initiate fitting a separate linear mixed model using chromosomeX kinship only for analyzing markers on chromosomeX. This approach is expected to be faster than the above option, but with less power, although type I error is also expected to be under control.
* Male genotypes for variants in nonPAR region are coded to be 0 or 2. If a male is heterozygous in nonPAR region, then the genotype of that male sample is considered missing and will be imputed using mean genotype.
