Project description:This experiment was specifically designed to measure neural targets of Shh signaling, we sought to profile the genes upregulated by Hh signaling in the ventral neural tube to obtain a valid dataset. To obtain ventral-specific markers, we generated retinoic acid-treated EBs grown in the presence or absence of HH-Ag. We did not observe induction of ventral Hh markers in RA-treated constitutive Gli1FLAG EBs and used these for the control, baseline set. The presence of FoxA2, Nkx2.9 and Nkx6.1 amongst the top 10 genes based on expression levels suggests that profiling significantly enriches for Hh-dependent cell types. As expected, the benchmark standard Gli1 was not up-regulated in our array, since it is constitutively expressed in the control as well. Keywords: neural progenitors, embryoid bodies, differentiation, Hedgehog, retinoic acid
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.