Also, the reporter was gorgeous, and her challenging expression suggested that if I answered "no", she would roll her eyes and end the conversation.
However, examples of challenging functional expression of bacterial genes encoding Fe S cluster harboring enzymes in eukaryotes have been reported.
The choice of a housekeeping gene can often be quite challenging, as expression is usually not the same across different CHO cell lines and clones, and can also vary according to the physiological state of the cells.
Identifying appropriate reference genes for data normalization and validating them on representative samples is a challenging problem in expression profiling, because the expression of all genes seem to be regulated under some conditions.
Disharmony between codon usage patterns for Plasmodium falciparum malaria parasite target genes and E. coli has proven particularly challenging for heterologous expression in E. coli owing to the 80% AT bias in the structural genes from P. falciparum [24].
However, things become more challenging when using expression data.
While technically challenging, restoring MeCP2 expression could therefore be considered for therapeutic approaches.
Identification of novel imprinted genes is particularly challenging because monoallelic expression may occur only in one of several possible isoforms, only in particular tissues, or only during particular stages of development.
Table 8 shows the results of simulation 3, a more challenging situation where expression levels varied with mixed fold-changes ranging from as small as less than 1.5 to 4. Furthermore, there were two change points in a non-monotonic trend for each gene in this simulation.
This makes downstream analyses inefficient and biological interpretations of similarities and differences in spatial expression patterns challenging, particularly when using automated tools for analyzing expression patterns of large number of images.
