Try Before You Buy: Are There Benefits to a Random Trial Period before Students Choose Their Collaborative Teams?

The cognitive and performance benefits of group work in undergraduate courses depend on understanding how to structure groups to promote communication and comfort while also promoting diversity and reducing conflict. The current study utilized social network analysis combined with self-reported survey data from 555 students in 155 groups to understand how students identified group members whom they wished to work with. Students' willingness to work with their peers was positively associated with behavioral traits pertaining to attention, participation, and preparedness in class. We tested whether preventing students from choosing their group members until completing a multiweek period of random assignment to different groups each week influenced group selection criteria, and we found little effect. Students continued to depend on demographic similarities such as gender and ethnicity when selecting groupmates and enforcing random interactions before the group formation did not influence group satisfaction and/or grades. Random interactions before group formation did influence the willingness of students to continue working with peers who were persistently poorly rated based on behavioral attributes and contribution to the group work. Thus, the effort of random assignment could be beneficial to identify struggling students and improve collaboration.

Piebaldism and chromatophore development in reptiles are linked to the tfec gene.

Reptiles display great diversity in color and pattern, yet much of what we know about vertebrate coloration comes from classic model species such as the mouse and zebrafish.1,2,3,4 Captive-bred ball pythons (Python regius) exhibit a remarkable degree of color and pattern variation. Despite the wide range of Mendelian color phenotypes available in the pet trade, ball pythons remain an overlooked species in pigmentation research. Here, we investigate the genetic basis of the recessive piebald phenotype, a pattern defect characterized by patches of unpigmented skin (leucoderma). We performed whole-genome sequencing and used a case-control approach to discover a nonsense mutation in the gene encoding the transcription factor tfec, implicating this gene in the leucodermic patches in ball pythons. We functionally validated tfec in a lizard model (Anolis sagrei) using the gene editing CRISPR/Cas9 system and TEM imaging of skin. Our findings show that reading frame mutations in tfec affect coloration and lead to a loss of iridophores in Anolis, indicating that tfec is required for chromatophore development. This study highlights the value of captive-bred ball pythons as a model species for accelerating discoveries on the genetic basis of vertebrate coloration.

Evolution of a chordate-specific mechanism for myoblast fusion.

Vertebrate myoblast fusion allows for multinucleated muscle fibers to compound the size and strength of mononucleated cells, but the evolution of this important process is unknown. We investigated the evolutionary origins and function of membrane-coalescing agents Myomaker and Myomixer in various groups of chordates. Here, we report that Myomaker likely arose through gene duplication in the last common ancestor of tunicates and vertebrates, while Myomixer appears to have evolved de novo in early vertebrates. Functional tests revealed a complex evolutionary history of myoblast fusion. A prevertebrate phase of muscle multinucleation driven by Myomaker was followed by the later emergence of Myomixer that enables the highly efficient fusion system of vertebrates. Evolutionary comparisons between vertebrate and nonvertebrate Myomaker revealed key structural and mechanistic insights into myoblast fusion. Thus, our findings suggest an evolutionary model of chordate fusogens and illustrate how new genes shape the emergence of novel morphogenetic traits and mechanisms.