We still have many challenging issues for association mapping problems.
However, the search for modifier genes is very challenging and disease associations are difficult to establish, because the contribution of a single modifier to the phenotype may be small and can be masked by other influencing factors, such as environment and ethnicity, as well as individual genetic background.
One of the crucial challenging factors is in association with the expression levels, stability, and cost-effectiveness of the cellulose-degrading enzymes (cellulases).
Testing this association is challenging, because we only know the physical location of the beta-defensin CNV blocks in two CEPH families.
Moreover, it is very challenging to assess the association between the mutation frequency difference and functional roles of TSGs and OCGs by both computational and experimental examination.
In genome-enabled prediction of traits in animal and plant breeding, building appropriate models can be extremely challenging, especially when the association between predictors and target variable involves non-additive effects [ 1- 4].
The long latency between smoking exposure and the development of cancer might make this association more challenging to demonstrate through epidemiologic studies in populations outside prison that are more mobile and might experience a lower intensity of exposure to smoke than people in prisons.
This is not unusual for any child, let alone one who has bounced around a bit and is still torn about previous associations, including challenging issues with her birth mother and failed recent fostering attempts.
We have previously used NBDPS data to show that antidepressant prescription patterns have changed over time, 5 making it more challenging to study these associations.
Furthermore, the positive associations between challenging behaviour and degree of intellectual disability, as well as the higher rates in people with autism compared with Down's syndrome, were as expected.
