A team from the University of California, Davis, addresses the performance of resequencing arrays in uncovering mutations linked to congenital myasthenic syndromes. Ricardo Maselli and his colleagues found that their custom-made arrays were highly specific and reproducible, but missed one of the 23 missense mutations and all of the seven indel mutations. In this case, the authors recommend assaying for common indels by capillary sequencing first. Finnish researchers compared the genomes of the Bordetella pertussis strains that have been circulating through the Finnish population over the last 50 years to the genome of the vaccine strain. Using oligonucleotide microarrays, Eriikka Heikkinen and her collaborators saw that pertussis gradually lost genes, especially ones involved in inorganic ion transport and metabolism. University of Southern California researchers led by Timothy Triche experimentally compared and cross-validated conventional and exon-only expression arrays. The scientists assessed the different Affymetrix arrays by evaluating their precision, specificity, and sensitivity in uncovering differential expression and found the two methods had a high agreement.