Testis transcriptional profiling of males deriving from two high fertility mouse lines (FL1, FL2) which have been long-term selected for the characteristics large and heavy litters in comparison to randomly selected control line (Ctrl). Mus musculus

As generally known, reproduction is referred to as a couple’s challenge. Many genes generally coding for reproduction performance are shared by both sexes. For investigating the impact of ‘high fertility’ breeding on murine males testis transcriptomic profile was examined of two worldwidely unique outbred long-term mouse lines which have been selected for large and heavy litters - Fertility Lines 1 and 2 (FL1, FL2); also known as DUK and DUC. After >170 generations of generally female focused breeding both high fertile mouse lines dramatically increased the number of offspring as well as the total litter weight up to 180%, which is additionally accompanied by raised ovulation rate as could be shown by previous data. Concomitantly with the improved fertility phenotype, for the FL males several line-specific phenotypic characteristics could already be revealed like physiological parameters (e.g. higher bodyweight, accelerated puberty and life expectancy), behavioural parameters (e.g. explorative behaviour in an open field and decreased endurance fitness on a treadmill) or testicular cell type composition (e.g. altered haploid and diploid cell content shown by flow cytometric analysis). By this combination of phenotypic characterization and profound transcriptomic profiling we hope to ensure for future perspective that these genetically heterogeneous mouse models will provide new insights into molecular and cellular mechanisms of enhancing male fertility. Overall design: Two separated microarray experiments (sets) were performed. Initially, for array set I each testis transcriptome of 8 mouse bucks per line was hybridized to 8 single microarray chips (n=8). These males are deriving from the 4th of entirely 5 replicates of a recently accomplished comprehensive two-factorial breeding experiment with the aim to scrutinize the impact of males and females on fertility parameters (recently submitted (08.16)). Beside the accompanying effect of being able to correlate breeding experiment observations with gene expression results, along the first array set we had the objective to develop a first profound hint about differential gene expression between these three lines. The resulting lists were experimentally verified with a second microarray set which was based on testis samples from 8 biologically independent bucks per line also involved in the two-factorial breeding experiment, 2nd replicate (n=8). Contrary to the first array set, a testis-RNA pool of the separated line specimens had been generated before these line pools were hybridized to one microarray regarded as pool-chip. By means of this approach we ensured a profound verification of the entirety of gained gene expression results. This handily served for exclusion of ‘false positive’ transcripts which were initially indicated as differentially expressed but then could not keep validity in biologically independent reevaluation.