Heritable variation is the raw material for evolutionary change, and understanding its genetic basis is one of the central problems in modern biology. We investigated the genetic basis of a classic phenotypic dimorphism in the nematode Caenorhabditis elegans. Males from many natural isolates deposit a copulatory plug after mating, whereas males from other natural isolates-including the standard wild-type strain (N2 Bristol) that is used in most research laboratories-do not deposit plugs 1 . The copulatory plug is a gelatinous mass that covers the hermaphrodite vulva, and its deposition decreases the mating success of subsequent males 2 . We show that the plugging polymorphism results from the insertion of a retrotransposon into an exon of a novel mucin-like gene, plg-1, whose product is a major structural component of the copulatory plug. The gene is expressed in a subset of secretory cells of the male somatic gonad, and its loss has no evident effects beyond the loss of male mate-guarding. Although C. elegans descends from an obligate-outcrossing, malefemale ancestor 3, 4 , it occurs primarily as self-fertilizing hermaphrodites 5-7 . The reduced selection on male-male competition associated with the origin of hermaphroditism may have permitted the global spread of a loss-of-function mutation with restricted pleiotropy.

Background It is common practice to use a combination approach of computed tomography (CT) scan followed by upright radiographs when assessing traumatic thoracolumbar (TL) vertebral fractures. The purpose of this study was to determine the clinical utility of upright spine radiographs in the setting of traumatic TL fracture management. Our null hypothesis is that upright TL radiographs rarely change management of acute vertebral fractures. Methods A retrospective study was performed on patients with an initial plan of non-operative management for a TL fracture between January 2014 and June 2020 at a single Level 1 trauma center. Patients were followed from time of initial consult to either conversion to surgery (operative) or last available outpatient follow up imaging (non-operative). Lateral kyphotic angle of the fractured vertebra and anterior vertebral body height% loss on initial CT, first upright radiograph, and endpoint upright radiograph imaging were measured. Measurements were compared between and within operative and non-operative groups using t-tests and Mann-Whitney U tests when appropriate. P-values ≤ 0.05 were considered statistically significant. Results The study included 70 patients with an average age of 54 years and 37 (52.9%) were women. Six (8.6%) of 70 patients had a change from non-operative to operative management based on upright radiographs. The mean (standard deviation) change in degrees of kyphosis from CT scan to first X-ray was 4.6 (7.0) in the non-operative group and 11.5 (8.1) in the operative group (P = 0.03). Delta degrees of kyphosis from CT scan to endpoint X-ray was 6.4 (9.0) and 16.2 (6.2) in the non-operative and operative groups, respectively (P = 0.01). In the operative group, mean degrees of kyphosis increased from 1.6 (7.6) in initial CT to 13.1 (8.9) in first X-ray (P = 0.02). First X-ray mean anterior body height% loss was 37.5 (17.6) and 53.2 (16.1) in the non-operative and operative groups, respectively (P = 0.04). Conclusions Upright radiographs are useful in guiding traumatic vertebral fracture management decisions. Larger studies are needed to determine the degree of change in kyphosis between CT and first standing radiograph that is suggestive of operative management. Trial registration number and date of registration Not applicable.

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Background Many prospective patients remain wary of the effects that glabellar muscle paralysis may have on their ability to normally communicate emotion with their face. Objective We undertook a direct empirical test of the effects of glabellar onabotulinum toxin type A injections on the ability to convey 6 universally recognized facial expressions of emotion. Methods Fifty-two female subjects (“expressors”) were recorded on hidden camera while viewing video clips intended as a mood induction procedure that stimulates the 6 cardinal emotions (amusement, anger, disgust, fear, sadness, surprise). The subjects were then injected with 25 units of onabotulinum toxin A in the glabellar region. The subjects returned 1 month later and were again recorded while being spontaneously induced to express emotion. All video clips from both time periods from the 10 maximal expressors were extracted and shown to a group of 31 “perceivers” who rated the facial expressions for intensity (Likert 1–7) and identity of emotion (percent correct emotion identified). Results Glabellar paralysis significantly diminished mean perceived intensity of anger (50.4% relative reduction, P < 0.001) and surprise (20.6% relative reduction, P < 0.001). The mean intensity of disgust increased (39.0%, P < 0.001). Importantly, however, glabellar paralysis did not result in a significant change in observers’ ability to discern provoked cardinal emotions. Conclusions We believe these findings provide a measure of reassurance to patients and their providers that the use of onabotulinum toxin A to paralyze the glabellar musculature for aesthetic purposes may not pose a meaningful risk to the overall ability to express emotion during social interaction. Level of Evidence: 4