Background: In genetic studies, the quality of DNA samples is tested first. Samples that are
low-quality are not used. Some studies involve minority ethnic groups. And example is admixed
African American. These studies often have small sample sizes. It is important to make sure
samples are not discarded unnecessarily. This may happen by using quality control (QC)
thresholds for homogenous groups. These may not be appropriate for an admixed group.
Researchers want to study samples that failed certain QC tests. They want to see if this has
to do with the ancestry of the outliers or the quality of the samples.
To study samples that fail heterozygosity and sample genotype call rate QC. To see if the
failing rates have to do with the ancestry composition of the outliers or the quality of the
No new participants. Researchers will review data that has already been collected.
Researchers will study DNA samples in a lab.
The samples will not include data that can identify the person the sample came from.