Combining single-cell genomics and lineage tracing, scientists from the University of Pennsylvania reveal the genomic, epigenomic, and biophysical drivers behind the formation of the lung alveolus. The lung alveolus develops during the late embryonic and early postnatal stages of life, but the intracellular signaling that drives this process remains poorly characterized. To address this knowledge gap, the investigators generated a single-cell RNA sequencing atlas of the developing mouse lung at different time points, which they analyzed to identify alveolar type 1 (AT1) epithelial cells as a distinct signaling hub. As they report in Science, they then used lineage tracing to demonstrate that AT1 progenitors align with receptive, force-exerting myofibroblasts in a spatial and temporal manner. Single-cell chromatin accessibility and pathway expression analysis further showed that AT1-restricted ligands are required for myofibroblasts and alveolar formation.
A large-scale genome-wide association study appearing in Science Advances uncovers a previously unknown genetic loci for eye color. In the study, an international team led by investigators from King's College London carried out a GWAS involving nearly 200,000 Europeans from 10 populations. They find 124 independent associations arising from 61 discrete genomic regions, including 50 novel eye color-associated genetic loci. In addition to evidence for genes in melanin pigmentation, they uncover associations with genes involved in iris morphology and structure. Further analysis in a group of Asian participants suggests that iris pigmentation variation in Asians is genetically similar to Europeans, although with a different effect size. The findings, the study's authors write, explain more than 50 percent of eye color phenotypic variation in Europeans and demonstrate that eye color is a genetically highly complex human trait, similar to hair and skin color. GenomeWeb has more on this, here.