SPEECHLESS duplication in grasses expands potential for environmental regulation of stomatal development.

Plants acquire atmospheric carbon dioxide for photosynthesis while minimizing water loss and do so by regulating stomatal function and development. The ancestral basic helix-loop-helix transcription factor (TF) gene that drove stomata production in early land plants diversified in sequence and function to become paralogs SPEECHLESS (SPCH), MUTE, and FAMA. Extant angiosperms use these three TFs and their heterodimer partners to regulate stomatal cell identities.

Multi-scale dynamics influence the division potential of stomatal lineage ground cells in Arabidopsis.

During development, many precursor lineages are flexible, producing variable numbers and types of progeny cells. What determines whether precursors differentiate or continue dividing? Here we take a quantitative approach that combines long-term live imaging, statistical modeling and computational simulations to probe the developmental flexibility of stomatal lineage ground cells (SLGC) in Arabidopsis leaves. We discover that cell size is a strong predictor of SLGC behaviour and that cell size is linked to division behaviour at multiple spatial scales.

Century-long timelines of herbarium genomes predict plant stomatal response to climate change.

Dissecting plant responses to the environment is key to understanding whether and how plants adapt to anthropogenic climate change. Stomata, plants' pores for gas exchange, are expected to decrease in density following increased CO concentrations, a trend already observed in multiple plant species. However, it is unclear whether such responses are based on genetic changes and evolutionary adaptation.

Interspecies transcriptomics identify genes that underlie disproportionate foot growth in jerboas.

Despite the great diversity of vertebrate limb proportion and our deep understanding of the genetic mechanisms that drive skeletal elongation, little is known about how individual bones reach different lengths in any species. Here, we directly compare the transcriptomes of homologous growth cartilages of the mouse (Mus musculus) and bipedal jerboa (Jaculus jaculus), the latter of which has "mouse-like" arms but extremely long metatarsals of the feet. Intersecting gene-expression differences in metatarsals and forearms of the two species revealed that about 10% of orthologous genes are associated with the disproportionately rapid elongation of neonatal jerboa feet.

Evolutionary loss of foot muscle during development with characteristics of atrophy and no evidence of cell death.

Many species that run or leap across sparsely vegetated habitats, including horses and deer, evolved the severe reduction or complete loss of foot muscles as skeletal elements elongated and digits were lost, and yet the developmental mechanisms remain unknown. Here, we report the natural loss of foot muscles in the bipedal jerboa, . Although adults have no muscles in their feet, newborn animals have muscles that rapidly disappear soon after birth.