However, since we do not expect the existence of true heterozygotes in a haploid genome, we refer to these variants as presently unexplained non-uniform sequences.
Subtraction of the surprisingly large number of sequence variants found in both the wild type and mutant genomes, but not in a previously sequenced reference genome (as well as identification of non-uniform sequences and alignment artifacts) allowed Timmermann et al. to quickly narrow their search to four candidate mutations predicted to cause amino acid changes in proteins.
This approach permits a flexible cluster definition that can be applied to most effectively identify non-random or non-uniform sequence motif distribution.
To validate the correctness of our mathematical approach defining non-randomness and non-uniform sequence motif distribution, we analyzed the IS distribution and presence of CIS in 2 successful clinical SCID-X1 studies [29,30, unpublished data].
The contributing sites have been shown to have positional preference towards annotated transcriptional start sites of the factors, which cannot be explained by a bias caused by GC content or non-uniform sequence conservation.
Even if the null hypothesis of random uniform allocation is not adequate, as it is known from retroviral vector integration [31], our calculations can address segments of the genome located between sites of predilection for virus integration and can be extended to address non-uniform sequence motif distributions.
The most important reasons for these complications are usually sequencing errors, repeat sequences in the target genome, non-uniform sequencing depth and limited read length of NGS data.
A subsample from the main dataset was used for richness and diversity calculation in an attempt to decrease bias caused by non-uniform sequence depth and some low sequence number samples.
To further investigate the function of the triphosphate, three 'GC' palindromic blunt-ended RNA duplexes with 5′triphosphates of lengths 10, 12 and 22 were tested for stimulation of RIG-I ATPase activity, as well as a 5′triphosphorylated 12-mer, 5′pppCM12, containing a palindromic but non-uniform sequence including all four nucleotides (Fig 4; supplementary Fig S2 online).
Frequently, the quality of the target- template sequence alignment is non-uniform along the sequence: parts can be modeled with a high confidence, whereas other parts differ strongly from the template.
As the error rate is high and the distribution of errors across sites is non-uniform in next generation sequencing (NGS) data, it has been a challenge to estimate DNA polymorphism accurately from NGS data.
