Unequal patterns in research effort can result in inaccurate assessments of species extinction risk or ineffective management. A group of notable conservation concern are tropical island endemic birds, many of which are also forest-dependent, which increases their vulnerability to extinction. Yet, island bird species have received limited research attention compared to their continental congeners, despite this taxon being globally regarded as well-studied. We used the insular Caribbean, a globally important endemism hotspot with high rates of deforestation, to explore research bias of island and regional endemic forest-dependent birds. A review of the published literature (n = 992) found no significant increase in the number of studies over the search period. Research effort was significantly higher among species with threatened status, long generation time, wide habitat breadth and low to intermediate elevational distributions. Among family groups, the Psittacidae received the highest research effort, while the Cuculidae were the most underrepresented family (30-fold higher and six-fold less than expected, respectively). We found geographic biases in effort, with Jamaica having six-fold less and Puerto Rico eight times more research than expected for their level of endemism. These patterns likely reflect individual interests and limited capacity and funding, typical of Small Island Developing States. With over 50% of species in this review having declining population trends, we recommend prioritizing research that emphasises conservation-and management-relevant data across underrepresented families and islands, by fostering greater collaboration between researchers, practitioners and the existing local amateur ornithological community.

The mitotic checkpoint (also called spindle assembly checkpoint, SAC) is a signaling pathway that safeguards proper chromosome segregation. Correct functioning of the SAC depends on adequate protein concentrations and appropriate stoichiometries between SAC proteins. Yet very little is known about the regulation of SAC gene expression. Here, we show in the fission yeast Schizosaccharomyces pombe that a combination of short mRNA half-lives and long protein half-lives supports stable SAC protein levels. For the SAC genes mad2 + and mad3 + , their short mRNA half-lives are caused, in part, by a high frequency of nonoptimal codons. In contrast, mad1 + mRNA has a short half-life despite a higher frequency of optimal codons, and despite the lack of known RNAdestabilizing motifs. Hence, different SAC genes employ different strategies of expression. We further show that Mad1 homodimers form co-translationally, which may necessitate a certain codon usage pattern. Taken together, we propose that the codon usage of SAC genes is fine-tuned to ensure proper SAC function. Our work shines light on gene expression features that promote spindle assembly checkpoint function and suggests that synonymous mutations may weaken the checkpoint.

Stochastic variation in gene products (“noise”) is an inescapable by-product of gene expression and can have profound consequences on cellular physiology. The least variation is seen for constitutively expressed genes, whose mRNA numbers in the population are commonly assumed to be Poisson-distributed, i.e. showing a variance equal to the mean. Here, we show that specific constitutively expressed cell division genes inS. pombeshow considerably lower variance in mRNA numbers, classifying them as sub-Poissonian. Importantly, the sub-Poissonian nature is more pronounced in the cytoplasm than the nucleus. Modeling indicates that the dynamics of cytoplasmic mRNA degradation and nuclear export are key in reducing the variance-to-mean ratio in the cytoplasm. Our findings suggest that constitutively expressed genes are not a homogenous group with respect to expression noise. Instead, they can differ in gene expression dynamics to create a range of mRNA distributions, whose lower limit is sub-Poissonian.

Circadian RNA expression is essential to ultimately regulate a plethora of downstream rhythmic biochemical, physiological, and behavioral processes. Both transcriptional and post-transcriptional mechanisms are considered important to drive rhythmic RNA expression, however, the extent to which each regulatory process contributes to the rhythmic RNA expression remains controversial. To systematically address this, we monitored RNA dynamics using metabolic RNA labeling technology during a circadian cycle in mouse fibroblasts. We find that rhythmic RNA synthesis is the primary contributor of 24 hr RNA rhythms, while rhythmic degradation is more important for 12 hr RNA rhythms. These rhythms were predominantly regulated by Bmal1 and/or the core clock mechanism, and interplay between rhythmic synthesis and degradation has a significant impact in shaping rhythmic RNA expression patterns. Interestingly, core clock RNAs are regulated by multiple rhythmic processes and have the highest amplitude of synthesis and degradation, presumably critical to sustain robust rhythmicity of cell-autonomous circadian rhythms. Our study yields invaluable insights into the temporal dynamics of both 24 hr and 12 hr RNA rhythms in mouse fibroblasts.

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