Understanding microchromosomal organization and evolution in four representative woodpeckers (Picidae, Piciformes) through BAC-FISH analysis.

The genome organization of woodpeckers has several distinctive features e.g., an uncommon accumulation of repetitive sequences, enlarged Z chromosomes, and atypical diploid numbers. Despite the large diversity of species, there is a paucity of detailed cytogenomic studies for this group and we thus aimed to rectify this. Genome organization patterns and hence evolutionary change in the microchromosome formation of four species (Colaptes campestris, Veniliornis spilogaster, Melanerpes candidus, and Picumnus nebulosus) was established through fluorescence in situ hybridization using bacterial artificial chromosomes originally derived from Gallus gallus and Taeniopygia guttata. Findings suggest that P. nebulosus (2n = 110), which was described for the first time, had the most basal karyotype among species of Picidae studied here, and probably arose as a result of fissions of avian ancestral macrochromosomes. We defined a new chromosomal number for V. spilogaster (2n = 88) and demonstrated microchromosomal rearrangements involving C. campestris plus a single, unique hitherto undescribed rearrangement in V. spilogaster. This comprised an inversion after a fusion involving the ancestral microchromosome 12 (homologous to chicken microchromosome 12). We also determined that the low diploid number of M. candidus is related to microchromosome fusions. Woodpeckers thus exhibit significantly rearranged karyotypes compared to the putative ancestral karyotype.

Understanding the chromosomal evolution in cuckoos (Aves, Cuculiformes): a journey through unusual rearrangements.

The Cuculiformes are a family of over 150 species that live in a range of habitats, such as forests, savannas, and deserts. Here, bacterial artificial chromosome (BAC) probes (75 from chicken and 14 from zebra finch macrochromosomes 1-10 +ZW and for microchromosomes 11-28 (except 16)) were used to investigate chromosome homologies between chicken and the squirrel cuckoo (Piaya cayana). In addition, repetitive DNA probes were applied to characterize the chromosome organization and to explore the role of these sequences in the karyotype evolution of P. cayana. We also applied BAC probes for chicken chromosome 17 and Z to the guira cuckoo (Guira guira) to test whether this species has an unusual Robertsonian translocation between a microchromosome and the Z chromosome, recently described in the smooth-billed ani (Crotophaga ani). Our results revealed extensive chromosome reorganization with inter- and intrachromosomal rearrangements in P. cayana, including a conspicuous chromosome size and heterochromatin polymorphism on chromosome pair 20. Furthermore, we confirmed that the Z-autosome Robertsonian translocation found in C. ani is also found in G. guira, not P. cayana. These findings suggest that this translocation occurred prior to the divergence between C. ani and G. guira, but after the divergence with P. cayana.

Validation of the Music Therapy Assessment Tool for Awareness in Disorders of Consciousness With the Coma Recovery Scale-Revised.

OBJECTIVE: To examine (1) the concurrent validity of the Music Therapy Assessment Tool for Awareness in Disorders of Consciousness (MATADOC) with the criterion standard Coma Recovery Scale-Revised (CRS-R) for outcomes of awareness in patients with prolonged disorders of consciousness (PDoC), (2) the relationship between MATADOC items and CRS-R function subscales in similar domains, and (3) determine if items/function subscales measure different constructs. DESIGN: A prospective multicentric blinded study with repeated concurrent measures. SETTING: Three inpatient rehabilitation units. PARTICIPANTS: Convenience sample of 74 adults with PDoC (N=74). MAIN OUTCOME MEASURES: The MATADOC protocol elicits behavioral responsiveness using live music in 5 tasks. A total score ranges 0-10 scoring behaviors across 14-items. The CRS-R uses a language-based protocol and scores observed responses ranging from 0-23 in 6 function subscales. Both measures were delivered at 4 concurrent time points over 2 weeks. RESULTS: Fair (κ=0.238, P=.006) ranging to moderate (κ=0.419, P<.001) significant agreement was found between CRS-R and MATADOC diagnostic outcomes. Fair-borderline moderate significant agreement was found for overall diagnostic outcomes across all diagnostic categories (κ=0.397, P=.001). There was moderate significant agreement between measures for motor scores (0.551≤κ≤0.571, P<.001) and visual outcomes (0.192≤κ≤0.415, .001≤P<.005) but no agreement for item/function subscale outcomes assessing auditory responsiveness. Exploratory factor analysis of all items showed 2 factors, suggesting that MATADOC and CRS-R measure the same underlying latent variable (awareness) in different ways and could complement each other for diagnosis and intervention purposes. This was supported by scale analysis, which showed increased reliability when the 2 scales are used together rather than separately. CONCLUSIONS: Unlike the CRS-R, the music-based MATADOC scores auditory localization for complexity of response and categorizes these behaviors as conscious rather than reflexive. The MATADOC may supplement the CRS-R, having a particular role in interdisciplinary programming for providing a more robust assessment of auditory responsiveness because of using nonverbal musical stimuli.

Characterisation of eight cattle with Swyer syndrome by whole-genome sequencing.

Swyer syndrome is where an individual has the karyotype of a typical male yet is phenotypically a female. The lack of a (functional) SRY gene located on the Y-chromosome is implicated in some cases of the Swyer syndrome, although many Swyer individuals with an apparently fully functional SRY gene have also been documented. The present study undertook whole genome sequence analyses of eight cattle with suspected Swyer syndrome and compared their genome to that of both a control male and female. Sequence analyses coupled with female phenotypes confirmed that all eight individuals had the 60,XY sex reversal Swyer syndrome. Seven of the eight Swyer syndrome individuals had a deletion on the Y chromosome encompassing the SRY gene (i.e., SRY-). The eighth individual had no obvious mutation in the SRY gene (SRY+) or indeed in any reported gene associated with sex reversal in mammals; a necropsy was performed on this individual. No testicles were detected during the necropsy. Histological examination of the reproductive tract revealed an immature uterine body and horns with inactive glandular tissue of normal histological appearance; both gonads were elongated, a characteristic of most reported cases of Swyer in mammals. The flanking sequence of 11 single nucleotide polymorphisms within 10 kb of the SRY gene are provided to help diagnose some cases of Swyer syndrome. These single nucleotide polymorphisms will not, however, detect all cases of Swyer syndrome since, as evidenced from the present study (and other studies), some individuals with the Swyer condition still contain the SRY gene (i.e., SRY+).

A comparative analysis of SARS-CoV-2 antivirals characterizes 3CLpro inhibitor PF-00835231 as a potential new treatment for COVID-19.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiological agent of Coronavirus Disease 2019 (COVID-19). There is a dire need for novel effective antivirals to treat COVID-19, as the only approved direct-acting antiviral to date is remdesivir, targeting the viral polymerase complex. A potential alternate target in the viral life cycle is the main SARS-CoV-2 protease 3CLpro (Mpro). The drug candidate PF-00835231 is the active compound of the first anti-3CLpro regimen in clinical trials. Here, we perform a comparative analysis of PF-00835231, the pre-clinical 3CLpro inhibitor GC-376, and the polymerase inhibitor remdesivir, in alveolar basal epithelial cells modified to express ACE2 (A549+ACE2 cells). We find PF-00835231 with at least similar or higher potency than remdesivir or GC-376. A time-of-drug-addition approach delineates the timing of early SARS-CoV-2 life cycle steps in A549+ACE2 cells and validates PF-00835231's early time of action. In a model of the human polarized airway epithelium, both PF-00835231 and remdesivir potently inhibit SARS-CoV-2 at low micromolar concentrations. Finally, we show that the efflux transporter P-glycoprotein, which was previously suggested to diminish PF-00835231's efficacy based on experiments in monkey kidney Vero E6 cells, does not negatively impact PF-00835231 efficacy in either A549+ACE2 cells or human polarized airway epithelial cultures. Thus, our study provides in vitro evidence for the potential of PF-00835231 as an effective SARS-CoV-2 antiviral and addresses concerns that emerged based on prior studies in non-human in vitro models.Importance:The arsenal of SARS-CoV-2 specific antiviral drugs is extremely limited. Only one direct-acting antiviral drug is currently approved, the viral polymerase inhibitor remdesivir, and it has limited efficacy. Thus, there is a substantial need to develop additional antiviral compounds with minimal side effects and alternate viral targets. One such alternate target is its main protease, 3CLpro (Mpro), an essential component of the SARS-CoV-2 life cycle processing the viral polyprotein into the components of the viral polymerase complex. In this study, we characterize a novel antiviral drug, PF-00835231, which is the active component of the first-in-class 3CLpro-targeting regimen in clinical trials. Using 3D in vitro models of the human airway epithelium, we demonstrate the antiviral potential of PF-00835231 for inhibition of SARS-CoV-2.

Do sex chromosomes of snakes, monitor lizards, and iguanian lizards result from multiple fission of an "ancestral amniote super-sex chromosome"?

Sex chromosomes in some amniotes share linkage homologies with distantly related taxa in regions orthologous to squamate reptile chromosome 2 (SR2) and the snake W sex chromosome. Thus, the SR2 and W chromosomes may formerly have been part of a larger ancestral amniote super-sex chromosome. Comparison of various sex chromosomal linkage homologies in Toxicofera with those in other amniotes offers an excellent model to assess key cytological differences, to understand the mechanisms of amniote sex chromosome evolution in each lineage and the existence of an ancestral amniote super-sex chromosome. Chromosome maps of four species of Toxicofera were constructed using bacterial artificial chromosomes (BACs) derived from chicken and zebra finch libraries containing amniote sex chromosomal linkages. Different macrochromosome linkage homologies were highly conserved among Toxicofera, and at least two BACs (CH261-125F1 and CH261-40D6) showed partial homology with sex chromosomes of amniotes associated with SR2, which supports the hypothesis of an ancestral super-sex chromosome with overlaps of partial linkage homologies. The present data also suggest a possible multiple fission mechanism of an ancestral super-sex chromosome, which resulted in further development of various sex chromosomal linkages of Toxicofera based on particular properties that favored the role of sex chromosomes.

Cytotaxonomy of Gallinula melanops (Gruiformes, Rallidae): Karyotype evolution and phylogenetic inference.

Although Rallidae is the most diverse family within Gruiformes, there is little information concerning the karyotype of the species in this group. In fact, Gallinula melanops, a species of Rallidae found in Brazil, is among the few species studied cytogenetically, but only with conventional staining and repetitive DNA mapping, showing 2n=80. Thus, in order to understand the karyotypic evolution and phylogeny of this group, the present study aimed to analyze the karyotype of G. melanops by classical and molecular cytogenetics, comparing the results with other species of Gruiformes. The results show that G. melanops has the same chromosome rearrangements as described in Gallinula chloropus (Clade Fulica), including fission of ancestral chromosomes 4 and 5 of Gallus gallus (GGA), beyond the fusion between two of segments resultants of the GGA4/GGA5, also fusions between the chromosomes GGA6/GGA7. Thus, despite the fact that some authors have suggested the inclusion of G. melanops in genus Porphyriops, our molecular cytogenetic results confirm its place in the Gallinula genus.

Patterns of microchromosome organization remain highly conserved throughout avian evolution.

The structure and organization of a species genome at a karyotypic level, and in interphase nuclei, have broad functional significance. Although regular sized chromosomes are studied extensively in this regard, microchromosomes, which are present in many terrestrial vertebrates, remain poorly explored. Birds have more cytologically indistinguishable microchromosomes (~ 30 pairs) than other vertebrates; however, the degree to which genome organization patterns at a karyotypic and interphase level differ between species is unknown. In species where microchromosomes have fused to other chromosomes, they retain genomic features such as gene density and GC content; however, the extent to which they retain a central nuclear position has not been investigated. In studying 22 avian species from 10 orders, we established that, other than in species where microchromosomal fusion is obvious (Falconiformes and Psittaciformes), there was no evidence of microchromosomal rearrangement, suggesting an evolutionarily stable avian genome (karyotypic) organization. Moreover, in species where microchromosomal fusion has occurred, they retain a central nuclear location, suggesting that the nuclear position of microchromosomes is a function of their genomic features rather than their physical size.

Upgrading short-read animal genome assemblies to chromosome level using comparative genomics and a universal probe set.

Most recent initiatives to sequence and assemble new species' genomes de novo fail to achieve the ultimate endpoint to produce contigs, each representing one whole chromosome. Even the best-assembled genomes (using contemporary technologies) consist of subchromosomal-sized scaffolds. To circumvent this problem, we developed a novel approach that combines computational algorithms to merge scaffolds into chromosomal fragments, PCR-based scaffold verification, and physical mapping to chromosomes. Multigenome-alignment-guided probe selection led to the development of a set of universal avian BAC clones that permit rapid anchoring of multiple scaffolds to chromosomes on all avian genomes. As proof of principle, we assembled genomes of the pigeon (Columbia livia) and peregrine falcon (Falco peregrinus) to chromosome levels comparable, in continuity, to avian reference genomes. Both species are of interest for breeding, cultural, food, and/or environmental reasons. Pigeon has a typical avian karyotype (2n = 80), while falcon (2n = 50) is highly rearranged compared to the avian ancestor. By using chromosome breakpoint data, we established that avian interchromosomal breakpoints appear in the regions of low density of conserved noncoding elements (CNEs) and that the chromosomal fission sites are further limited to long CNE "deserts." This corresponds with fission being the rarest type of rearrangement in avian genome evolution. High-throughput multiple hybridization and rapid capture strategies using the current BAC set provide the basis for assembling numerous avian (and possibly other reptilian) species, while the overall strategy for scaffold assembly and mapping provides the basis for an approach that (provided metaphases can be generated) could be applied to any animal genome.

An analysis of the effects of using Zolpidem and an innovative multimodal interdisciplinary team approach in prolonged disorders of consciousness (PDOC).

Zolpidem has been used with mixed effects in patients presenting with Prolonged Disorders of Consciousness (PDOC). This single case report describes an interdisciplinary team (IDT) protocol combined with Zolpidem 10 mg in a single case of a patient in PDOC. 'Emily', a 44-year-old lady was admitted to a rehabilitation unit in Ireland one year post onset of subarachnoid haemorrhage. Standardized assessments diagnosed her as being in a minimally conscious state (MCS). An IDT protocol was devised to stimulate and record responses to sensory and pharmacological stimuli. The protocol was applied pre and post administration of Zolpidem 10 mg. Across standardized measures of awareness, improved results post-Zolpidem were recorded. Spontaneous, appropriate verbalization was the most significant change observed 30 min after administration of Zolpidem 10 mg. This ceased after approximately 2 h with Emily reverting to a non-verbal state. The combined effect of Zolpidem and the IDT protocol applied over an eight-week period resulted in durable functional and communicative gains for Emily, inferring neuro-plasticity. This report highlights the impact of a combined approach of intensive IDT intervention in conjunction with Zolpidem. The use of Zolpidem with this patient population warrants further investigation.

Chromosome map of the Siamese cobra: did partial synteny of sex chromosomes in the amniote represent "a hypothetical ancestral super-sex chromosome" or random distribution?

BACKGROUND: Unlike the chromosome constitution of most snakes (2n=36), the cobra karyotype shows a diploid chromosome number of 38 with a highly heterochromatic W chromosome and a large morphologically different chromosome 2. To investigate the process of sex chromosome differentiation and evolution between cobras, most snakes, and other amniotes, we constructed a chromosome map of the Siamese cobra (Naja kaouthia) with 43 bacterial artificial chromosomes (BACs) derived from the chicken and zebra finch libraries using the fluorescence in situ hybridization (FISH) technique, and compared it with those of the chicken, the zebra finch, and other amniotes. RESULTS: We produced a detailed chromosome map of the Siamese cobra genome, focusing on chromosome 2 and sex chromosomes. Synteny of the Siamese cobra chromosome 2 (NKA2) and NKAZ were highly conserved among snakes and other squamate reptiles, except for intrachromosomal rearrangements occurring in NKA2. Interestingly, twelve BACs that had partial homology with sex chromosomes of several amniotes were mapped on the heterochromatic NKAW as hybridization signals such as repeat sequences. Sequence analysis showed that most of these BACs contained high proportions of transposable elements. In addition, hybridization signals of telomeric repeat (TTAGGG)n and six microsatellite repeat motifs ((AAGG)8, (AGAT)8, (AAAC)8, (ACAG)8, (AATC)8, and (AAAAT)6) were observed on NKAW, and most of these were also found on other amniote sex chromosomes. CONCLUSIONS: The frequent amplification of repeats might involve heterochromatinization and promote sex chromosome differentiation in the Siamese cobra W sex chromosome. Repeat sequences are also shared among amniote sex chromosomes, which supports the hypothesis of an ancestral super-sex chromosome with overlaps of partial syntenies. Alternatively, amplification of microsatellite repeat motifs could have occurred independently in each lineage, representing convergent sex chromosomal differentiation among amniote sex chromosomes.

Novel tools for characterising inter and intra chromosomal rearrangements in avian microchromosomes.

Avian genome organisation is characterised, in part, by a set of microchromosomes that are unusually small in size and unusually large in number. Although containing about a quarter of the genome, they contain around half the genes and three quarters of the total chromosome number. Nonetheless, they continue to belie analysis by cytogenetic means. Chromosomal rearrangements play a key role in genome evolution, fertility and genetic disease and thus tools for analysis of the microchromosomes are essential to analyse such phenomena in birds. Here, we report the development of chicken microchromosomal paint pools, generation of pairs of specific microchromosome BAC clones in chicken, and computational tools for in silico comparison of the genomes of microchromosomes. We demonstrate the use of these molecular and computational tools across species, suggesting their use to generate a clear picture of microchromosomal rearrangements between avian species. With increasing numbers of avian genome sequences that are emerging, tools such as these will find great utility in assembling genomes de novo and for asking fundamental questions about genome evolution from a chromosomal perspective.

Reconstruction of gross avian genome structure, organization and evolution suggests that the chicken lineage most closely resembles the dinosaur avian ancestor.

BACKGROUND: The availability of multiple avian genome sequence assemblies greatly improves our ability to define overall genome organization and reconstruct evolutionary changes. In birds, this has previously been impeded by a near intractable karyotype and relied almost exclusively on comparative molecular cytogenetics of only the largest chromosomes. Here, novel whole genome sequence information from 21 avian genome sequences (most newly assembled) made available on an interactive browser (Evolution Highway) was analyzed. RESULTS: Focusing on the six best-assembled genomes allowed us to assemble a putative karyotype of the dinosaur ancestor for each chromosome. Reconstructing evolutionary events that led to each species' genome organization, we determined that the fastest rate of change occurred in the zebra finch and budgerigar, consistent with rapid speciation events in the Passeriformes and Psittaciformes. Intra- and interchromosomal changes were explained most parsimoniously by a series of inversions and translocations respectively, with breakpoint reuse being commonplace. Analyzing chicken and zebra finch, we found little evidence to support the hypothesis of an association of evolutionary breakpoint regions with recombination hotspots but some evidence to support the hypothesis that microchromosomes largely represent conserved blocks of synteny in the majority of the 21 species analyzed. All but one species showed the expected number of microchromosomal rearrangements predicted by the haploid chromosome count. Ostrich, however, appeared to retain an overall karyotype structure of 2n=80 despite undergoing a large number (26) of hitherto un-described interchromosomal changes. CONCLUSIONS: Results suggest that mechanisms exist to preserve a static overall avian karyotype/genomic structure, including the microchromosomes, with widespread interchromosomal change occurring rarely (e.g., in ostrich and budgerigar lineages). Of the species analyzed, the chicken lineage appeared to have undergone the fewest changes compared to the dinosaur ancestor.

A Bird's-Eye View of Chromosomic Evolution in the Class Aves.

Birds (Aves) are the most speciose of terrestrial vertebrates, displaying Class-specific characteristics yet incredible external phenotypic diversity. Critical to agriculture and as model organisms, birds have adapted to many habitats. The only extant examples of dinosaurs, birds emerged ~150 mya and >10% are currently threatened with extinction. This review is a comprehensive overview of avian genome ("chromosomic") organization research based mostly on chromosome painting and BAC-based studies. We discuss traditional and contemporary tools for reliably generating chromosome-level assemblies and analyzing multiple species at a higher resolution and wider phylogenetic distance than previously possible. These results permit more detailed investigations into inter- and intrachromosomal rearrangements, providing unique insights into evolution and speciation mechanisms. The 'signature' avian karyotype likely arose ~250 mya and remained largely unchanged in most groups including extinct dinosaurs. Exceptions include Psittaciformes, Falconiformes, Caprimulgiformes, Cuculiformes, Suliformes, occasional Passeriformes, Ciconiiformes, and Pelecaniformes. The reasons for this remarkable conservation may be the greater diploid chromosome number generating variation (the driver of natural selection) through a greater possible combination of gametes and/or an increase in recombination rate. A deeper understanding of avian genomic structure permits the exploration of fundamental biological questions pertaining to the role of evolutionary breakpoint regions and homologous synteny blocks.

Design and Synthesis of Clinical Candidate PF-06852231 (CVL-231): A Brain Penetrant, Selective, Positive Allosteric Modulator of the M4 Muscarinic Acetylcholine Receptor.

Selective activation of the M4 muscarinic acetylcholine receptor subtype offers a novel strategy for the treatment of psychosis in multiple neurological disorders. Although the development of traditional muscarinic activators has been stymied due to pan-receptor activation, muscarinic receptor subtype selectivity can be achieved through the utilization of a subtype of a unique allosteric site. A major challenge in capitalizing on this allosteric site to date has been achieving a balance of suitable potency and brain penetration. Herein, we describe the design of a brain penetrant series of M4 selective positive allosteric modulators (PAMs), ultimately culminating in the identification of 21 (PF-06852231, now CVL-231/emraclidine), which is under active clinical development as a novel mechanism and approach for the treatment of schizophrenia.

Should All Nurses Be Required to Complete Implicit Bias Training?

Bias mitigation requires a systematic approach.

A conserved karyotype? Chromosomal rearrangements in Charadrius collaris detected by BAC-FISH.

Charadriidae comprise 142 valid species and the most recent checklist for the occurrence of this family in Brazil describes 11 species. There are few chromosomal studies in Charadriidae, most of them using a conventional approach. In Charadrius, only five species had their karyotypes described by classical cytogenetics, of which four have 2n = 76 (C. hiaticula, C. dubius, C. vociferou and C. collaris) and one 2n = 78 (C. alexandrinus alexandrinus). Among these species, only Charadrius collaris had the karyotype studied by chromosome painting, which allowed the identification of chromosomal homeologies with the karyotypes of Gallus gallus (GGA) and Burhinus oedicnemus (BOE). According to the literature, studies performed with BAC-FISH using probes from Gallus gallus and Taeniopygia guttata (TGU) libraries have shown interactions between macro and microchromosomes and micro inversions in chromosomes previously considered conserved. Other studies have shown the fusion of several microchromosomes, forming new macrochromosomes, leading to a decrease in the 2n of some species. The present study aims to deepen the chromosomal information in Charadrius collaris through the application of BAC-FISH with probes from the GGA and TGU libraries, in order to investigate possible rearrangements within the apparently conserved karyotype of this species, and thus better clarify the evolutionary history of the species. Charadrius collaris presented 2n = 76 and fundamental number (FN) equal to 94. Comparative mapping of BAC probes from GGA and TGU in Charadrius collaris revealed hybridization signals from 26 macrochromosome probes. Probes from microchromosomes 9 to 28 of GGA were also used and revealed 31 hybridization signals. The karyotype is well conserved, but it contains a paracentric and a pericentric inversion on the CCO1 chromosome, a paracentric and a pericentric inversion on the CCO4 and the separation of GGA4 into CCO4 and CCO8, demonstrating that the BAC-FISH approach allows for greater data resolution. More studies are needed to improve the understanding of chromosomal evolution within the order Charadriiformes and thus clarify whether these characteristics demonstrated here are specific traits for Charadrius collaris or if other species share these characteristics.

An inverse agonist of orphan receptor GPR61 acts by a G protein-competitive allosteric mechanism.

GPR61 is an orphan GPCR related to biogenic amine receptors. Its association with phenotypes relating to appetite makes it of interest as a druggable target to treat disorders of metabolism and body weight, such as obesity and cachexia. To date, the lack of structural information or a known biological ligand or tool compound has hindered comprehensive efforts to study GPR61 structure and function. Here, we report a structural characterization of GPR61, in both its active-like complex with heterotrimeric G protein and in its inactive state. Moreover, we report the discovery of a potent and selective small-molecule inverse agonist against GPR61 and structural elucidation of its allosteric binding site and mode of action. These findings offer mechanistic insights into an orphan GPCR while providing both a structural framework and tool compound to support further studies of GPR61 function and modulation.

Discovery of the Potent and Selective MC4R Antagonist PF-07258669 for the Potential Treatment of Appetite Loss.

The melanocortin-4 receptor (MC4R) is a centrally expressed, class A GPCR that plays a key role in the regulation of appetite and food intake. Deficiencies in MC4R signaling result in hyperphagia and increased body mass in humans. Antagonism of MC4R signaling has the potential to mitigate decreased appetite and body weight loss in the setting of anorexia or cachexia due to underlying disease. Herein, we report on the identification of a series of orally bioavailable, small-molecule MC4R antagonists using a focused hit identification effort and the optimization of these antagonists to provide clinical candidate 23. Introduction of a spirocyclic conformational constraint allowed for simultaneous optimization of MC4R potency and ADME attributes while avoiding the production of hERG active metabolites observed in early series leads. Compound 23 is a potent and selective MC4R antagonist with robust efficacy in an aged rat model of cachexia and has progressed into clinical trials.

Dinosaurs: Comparative Cytogenomics of Their Reptile Cousins and Avian Descendants.

Reptiles known as dinosaurs pervade scientific and popular culture, while interest in their genomics has increased since the 1990s. Birds (part of the crown group Reptilia) are living theropod dinosaurs. Chromosome-level genome assemblies cannot be made from long-extinct biological material, but dinosaur genome organization can be inferred through comparative genomics of related extant species. Most reptiles apart from crocodilians have both macro- and microchromosomes; comparative genomics involving molecular cytogenetics and bioinformatics has established chromosomal relationships between many species. The capacity of dinosaurs to survive multiple extinction events is now well established, and birds now have more species in comparison with any other terrestrial vertebrate. This may be due, in part, to their karyotypic features, including a distinctive karyotype of around n = 40 (~10 macro and 30 microchromosomes). Similarity in genome organization in distantly related species suggests that the common avian ancestor had a similar karyotype to e.g., the chicken/emu/zebra finch. The close karyotypic similarity to the soft-shelled turtle (n = 33) suggests that this basic pattern was mostly established before the Testudine-Archosaur divergence, ~255 MYA. That is, dinosaurs most likely had similar karyotypes and their extensive phenotypic variation may have been mediated by increased random chromosome segregation and genetic recombination, which is inherently higher in karyotypes with more and smaller chromosomes.