A change of expression in the conserved signaling gene MKK7 is associated with a selective sweep in the western house mouse Mus musculus domesticus

Abstract

Changes in gene expression are known to occur between closely related species, but it is not yet clear how many of these are due to random fixation of allelic variants or due to adaptive events. In a microarray survey between subspecies of the Mus musculus complex, we identified the mitogen-activated protein-kinase-kinase MKK7 as a candidate for change in gene expression. Quantitative PCR experiments with multiple individuals from each subspecies confirmed a specific and significant up-regulation in the testis of M. m. domesticus. Northern blot analysis shows that this is due to a new transcript that is not found in other tissues, nor in M. m. musculus. A cis-trans test via allele specific expression analysis of the MKK7 gene in F1 hybrids between domesticus and musculus shows that the expression change is mainly caused by a mutation located in cis. Nucleotide diversity was found to be significantly reduced in a window of at least 20 kb around the MKK7 locus in domesticus, indicative of a selective sweep. Because the MKK7 gene is involved in modulating a kinase signalling cascade in a stress response pathway, it seems a plausible target for adaptive differences between subspecies, although the functional role of the new testis-specific transcripts will need to be further studied

The Phenomics and Expression Quantitative Trait Locus Mapping of Brain Transcriptomes Regulating Adaptive Divergence in Lake Whitefish Species Pairs (Coregonus sp.)

“…However, concordance between microarrays and RT-PCR may not be particularly strong in cases where individual variability is high and fold change in transcription is relatively low, or where a history of genome duplication has given rise to multiple related genes with high sequence similarity (Harr et al 2006;Morey et al 2006). In the case of the G-protein gene, it is possible that our RT-PCR primers amplified a paralog or distinct member of the G-protein gene family instead of the transcript for which expression data were collected on the microarray.…”

Genome‐wide analysis of alternative splicing evolution among Mus subspecies

“…This transcript (U93030) has been characterized as testis specific in laboratory strains of mice (Tournier et al. 1997) and has the same length (∼1.6 kb) as the transcript previously detected in wild domesticus (Harr et al. 2006).…”

“…The Map2k7 gene shows a dramatic difference in transcript usage in the testis of wild domesticus and musculus (Harr et al. 2006).…”

“…2007). Detailed analysis of one of these differentially expressed genes, mitogen‐activated protein kinase kinase 7 ( Map2k7 ), revealed that differences in expression level were due to the presence of a splice variant in M. m. domesticus that was absent in M. m. musculus (Harr et al. 2006).…”

“…A test case. Previous studies of the Map2k7 gene (Harr et al. 2006) revealed a large difference in transcript abundance in the testis between two house mouse subspecies, domesticus and musculus .…”