The genome of Citrus australasica reveals disease resistance and other species specific genes.

BACKGROUND: The finger lime (Citrus australasica), one of six Australian endemic citrus species shows a high natural phenotypic diversity and novel characteristics. The wide variation and unique horticultural features have made this lime an attractive candidate for domestication. Currently no haplotype resolved genome is available for this species. Here we present a high quality, haplotype-resolved reference genome for this species using PacBio HiFi and Hi-C sequencing. RESULTS: Hifiasm assembly and SALSA scaffolding resulted in a collapsed genome size of 344.2 Mb and 321.1 Mb and 323.2 Mb size for the two haplotypes. The nine pseudochromosomes of the collapsed genome had an N50 of 35.2 Mb, 99.1% genome assembly completeness and 98.9% gene annotation completeness (BUSCO). A total of 41,304 genes were predicted in the nuclear genome. Comparison with C. australis revealed that 13,661 genes in pseudochromosomes were unique in C. australasica. These were mainly involved in plant-pathogen interactions, stress response, cellular metabolic and developmental processes, and signal transduction. The two genomes showed a syntenic arrangement at the chromosome level with large structural rearrangements in some chromosomes. Genetic variation among five C. australasica cultivars was analysed. Genes related to defense, synthesis of volatile compounds and red/yellow coloration were identified in the genome. A major expansion of genes encoding thylakoid curvature proteins was found in the C. australasica genome. CONCLUSIONS: The genome of C. australasica present in this study is of high quality and contiguity. This genome helps deepen our understanding of citrus evolution and reveals disease resistance and quality related genes with potential to accelerate the genetic improvement of citrus.

Karyotypic Reshuffling in the Genus Rhipidomys (Rodentia: Cricetidae: Sigmodontinae) Revealed by Zoo-FISH.

INTRODUCTION: Rhipidomys is the second most specious and the most widespread genus of the tribe Thomasomyini. Chromosomal data have been an important tool in the taxonomy of the group that presents low variability of diploid number (2n) and highly variable fundamental numbers (FNs). Despite such diversity, the genus has been studied mainly by classical and banding cytogenetic techniques. METHODS: This study performed a comparative study between R. emiliae (2n = 44, FN = 52), R. macrurus (2n = 44, FN = 49), R. nitela (2n = 50, FN = 71), and R. mastacalis (2n = 44, FN = 72) using chromosome painting probes of two Oryzomyini species. RESULTS: Our analysis revealed pericentric inversion as the main rearrangement involved in the karyotype evolution of the group, although tandem fusions/fissions were also detected. In addition, we detected eight syntenic associations exclusive of the genus Rhipidomys, and three syntenic associations shared between species of the tribe Thomasomyini and Oryzomyini. CONCLUSION: Comparative cytogenetic analysis by ZOO-FISH on genus Rhipidomys supports a pattern of chromosomal rearrangement already suggested by comparative G-banding. However, the results suggest that karyotype variability in the genus could also involve the occurrence of an evolutionary new centromere.

Pan-cancer genome and transcriptome analyses of 1,699 paediatric leukaemias and solid tumours.

Analysis of molecular aberrations across multiple cancer types, known as pan-cancer analysis, identifies commonalities and differences in key biological processes that are dysregulated in cancer cells from diverse lineages. Pan-cancer analyses have been performed for adult but not paediatric cancers, which commonly occur in developing mesodermic rather than adult epithelial tissues. Here we present a pan-cancer study of somatic alterations, including single nucleotide variants, small insertions or deletions, structural variations, copy number alterations, gene fusions and internal tandem duplications in 1,699 paediatric leukaemias and solid tumours across six histotypes, with whole-genome, whole-exome and transcriptome sequencing data processed under a uniform analytical framework. We report 142 driver genes in paediatric cancers, of which only 45% match those found in adult pan-cancer studies; copy number alterations and structural variants constituted the majority (62%) of events. Eleven genome-wide mutational signatures were identified, including one attributed to ultraviolet-light exposure in eight aneuploid leukaemias. Transcription of the mutant allele was detectable for 34% of protein-coding mutations, and 20% exhibited allele-specific expression. These data provide a comprehensive genomic architecture for paediatric cancers and emphasize the need for paediatric cancer-specific development of precision therapies.

The genetic basis and cell of origin of mixed phenotype acute leukaemia.

Mixed phenotype acute leukaemia (MPAL) is a high-risk subtype of leukaemia with myeloid and lymphoid features, limited genetic characterization, and a lack of consensus regarding appropriate therapy. Here we show that the two principal subtypes of MPAL, T/myeloid (T/M) and B/myeloid (B/M), are genetically distinct. Rearrangement of ZNF384 is common in B/M MPAL, and biallelic WT1 alterations are common in T/M MPAL, which shares genomic features with early T-cell precursor acute lymphoblastic leukaemia. We show that the intratumoral immunophenotypic heterogeneity characteristic of MPAL is independent of somatic genetic variation, that founding lesions arise in primitive haematopoietic progenitors, and that individual phenotypic subpopulations can reconstitute the immunophenotypic diversity in vivo. These findings indicate that the cell of origin and founding lesions, rather than an accumulation of distinct genomic alterations, prime tumour cells for lineage promiscuity. Moreover, these findings position MPAL in the spectrum of immature leukaemias and provide a genetically informed framework for future clinical trials of potential treatments for MPAL.

Recent Australian Legislative Developments in the Regulation of Assisted Reproductive Technology.

This section considers the recent resurgence of regulatory interest in the field of assisted reproductive technology (ART) practices focusing on the new legislative framework in the Australian Capital Territory (ACT). It provides an overview of the Australian regulatory framework in this field and considers how the new legislation in the ACT sits alongside this framework. A detailed overview of the key provisions of the ACT legislation is provided, before considering whether the legislation goes far enough in addressing some of the more controversial issues in the field of ART.

Ancestral chromosomal signatures of Paenungulata (Afroteria) reveal the karyotype of Amazonian manatee (Trichechus inunguis, Sirenia: Trichechidae) as the oldest among American manatees.

BACKGROUND: Chromosomal painting in manatees has clarified questions about the rapid evolution of sirenians within the Paenungulata clade. Further cytogenetic studies in Afrotherian species may provide information about their evolutionary dynamics, revealing important insights into the ancestral karyotype in the clade representatives. The karyotype of Trichechus inunguis (TIN, Amazonian manatee) was investigated by chromosome painting, using probes from Trichechus manatus latirostris (TML, Florida manatee) to analyze the homeologies between these sirenians. RESULTS: A high similarity was found between these species, with 31 homologous segments in TIN, nineteen of which are whole autosomes, besides the X and Y sex chromosomes. Four chromosomes from TML (4, 6, 8, and 9) resulted in two hybridization signals, totaling eight acrocentrics in the TIN karyotype. This study confirmed in TIN the chromosomal associations of Homo sapiens (HSA) shared in Afrotheria, such as the 5/21 synteny, and in the Paenungulata clade with the syntenies HSA 2/3, 8/22, and 18/19, in addition to the absence of HSA 4/8 common in eutherian ancestral karyotype (EAK). CONCLUSIONS: TIN shares more conserved chromosomal signals with the Paenungulata Ancestral Karyotype (APK, 2n = 58) than Procavia capensis (Hyracoidea), Loxodonta africana (Proboscidea) and TML (Sirenia), where TML presents less conserved signals with APK, demonstrating that its karyotype is the most derived among the representatives of Paenungulata. The chromosomal changes that evolved from APK to the T. manatus and T. inunguis karyotypes (7 and 4 changes, respectively) are more substantial within the Trichechus genus compared to other paenungulates. Among these species, T. inunguis presents conserved traits of APK in the American manatee genus. Consequently, the karyotype of T. manatus is more derived than that of T. inunguis.

Selumetinib in Children with Inoperable Plexiform Neurofibromas.

BACKGROUND: No approved therapies exist for inoperable plexiform neurofibromas in patients with neurofibromatosis type 1. METHODS: We conducted an open-label, phase 2 trial of selumetinib to determine the objective response rate among patients with plexiform neurofibromas and to assess clinical benefit. Children with neurofibromatosis type 1 and symptomatic inoperable plexiform neurofibromas received oral selumetinib twice daily at a dose of 25 mg per square meter of body-surface area on a continuous dosing schedule (28-day cycles). Volumetric magnetic resonance imaging and clinical outcome assessments (pain, quality of life, disfigurement, and function) were performed at least every four cycles. Children rated tumor pain intensity on a scale from 0 (no pain) to 10 (worst pain imaginable). RESULTS: A total of 50 children (median age, 10.2 years; range, 3.5 to 17.4) were enrolled from August 2015 through August 2016. The most frequent neurofibroma-related symptoms were disfigurement (44 patients), motor dysfunction (33), and pain (26). A total of 35 patients (70%) had a confirmed partial response as of March 29, 2019, and 28 of these patients had a durable response (lasting ≥1 year). After 1 year of treatment, the mean decrease in child-reported tumor pain-intensity scores was 2 points, considered a clinically meaningful improvement. In addition, clinically meaningful improvements were seen in child-reported and parent-reported interference of pain in daily functioning (38% and 50%, respectively) and overall health-related quality of life (48% and 58%, respectively) as well as in functional outcomes of strength (56% of patients) and range of motion (38% of patients). Five patients discontinued treatment because of toxic effects possibly related to selumetinib, and 6 patients had disease progression. The most frequent toxic effects were nausea, vomiting, or diarrhea; an asymptomatic increase in the creatine phosphokinase level; acneiform rash; and paronychia. CONCLUSIONS: In this phase 2 trial, most children with neurofibromatosis type 1 and inoperable plexiform neurofibromas had durable tumor shrinkage and clinical benefit from selumetinib. (Funded by the Intramural Research Program of the National Institutes of Health and others; ClinicalTrials.gov number, NCT01362803.).

Somatic structural variation targets neurodevelopmental genes and identifies SHANK2 as a tumor suppressor in neuroblastoma.

Neuroblastoma is a malignancy of the developing sympathetic nervous system that accounts for 12% of childhood cancer deaths. Like many childhood cancers, neuroblastoma shows a relative paucity of somatic single-nucleotide variants (SNVs) and small insertions and deletions (indels) compared to adult cancers. Here, we assessed the contribution of somatic structural variation (SV) in neuroblastoma using a combination of whole-genome sequencing (WGS) of tumor-normal pairs (n = 135) and single-nucleotide polymorphism (SNP) genotyping of primary tumors (n = 914). Our study design allowed for orthogonal validation and replication across platforms. SV frequency, type, and localization varied significantly among high-risk tumors. MYCN nonamplified high-risk tumors harbored an increased SV burden overall, including a significant excess of tandem duplication events across the genome. Genes disrupted by SV breakpoints were enriched in neuronal lineages and associated with phenotypes such as autism spectrum disorder (ASD). The postsynaptic adapter protein-coding gene, SHANK2, located on Chromosome 11q13, was disrupted by SVs in 14% of MYCN nonamplified high-risk tumors based on WGS and 10% in the SNP array cohort. Expression of SHANK2 was low across human-derived neuroblastoma cell lines and high-risk neuroblastoma tumors. Forced expression of SHANK2 in neuroblastoma cells resulted in significant growth inhibition (P = 2.6 × 10-2 to 3.4 × 10-5) and accelerated neuronal differentiation following treatment with all-trans retinoic acid (P = 3.1 × 10-13 to 2.4 × 10-30). These data further define the complex landscape of somatic structural variation in neuroblastoma and suggest that events leading to deregulation of neurodevelopmental processes, such as inactivation of SHANK2, are key mediators of tumorigenesis in this childhood cancer.

Characterization of repetitive DNA on the genome of the marsh rat Holochilus nanus (Cricetidae: Sigmodontinae).

Repetitive DNA are sequences repeated hundreds or thousands of times and an abundant part of eukaryotic genomes. SatDNA represents the majority of the repetitive sequences, followed by transposable elements. The species Holochilus nanus (HNA) belongs to the rodent tribe Oryzomyini, the most taxonomically diverse of Sigmodontinae subfamily. Cytogenetic studies on Oryzomyini reflect such diversity by revealing an exceptional range of karyotype variability. However, little is known about the repetitive DNA content and its involvement in chromosomal diversification of these species. In the search for a more detailed understanding about the composition of repetitive DNA on the genome of HNA and other species of Oryzomyini, we employed a combination of bioinformatic, cytogenetic and molecular techniques to characterize the repetitive DNA content of these species. RepeatExplorer analysis showed that almost half of repetitive content of HNA genome are composed by Long Terminal Repeats and a less significant portion are composed by Short Interspersed Nuclear Elements and Long Interspersed Nuclear Elements. RepeatMasker showed that more than 30% of HNA genome are composed by repetitive sequences, with two main waves of repetitive element insertion. It was also possible to identify a satellite DNA sequence present in the centromeric region of Oryzomyini species, and a repetitive sequence enriched on the long arm of HNA X chromosome. Also, comparative analysis between HNA genome with and without B chromosome did not evidence any repeat element enriched on the supernumerary, suggesting that B chromosome of HNA is composed by a fraction of repeats from all the genome.

Chromosome evolution in Iberolacerta, a genus that deviates from the standard karyotype formula of Lacertidae.

This paper describes the preparation of flow-sorted chromosome paints from the Iberian Rock lizard Iberolacerta monticola, exemplifying their subsequent use in cross-species comparisons of chromosome painting. We carried out comparative analyses of chromosome evolution in the congeneric species I. galani and I. bonnali, as well as in two other species of Lacertini (Lacerta schreiberi and Timon lepidus) whose sex chromosomes were also studied through comparative genomic hybridization. Most species of Lacertini possess a diplod number of 2n = 38, with 36 acrocentric macrochromosomes and 2 microchromosomes. However, the nine species included in the genus Iberolacerta do not possess microchromosomes. Furthermore, very conspicuous differences from the standard Lacertini karyotype were observed in the three Pyrenean species of this genus, which included several biarmed metacentrics and a Z1Z2W multiple sex-chromosome system. With the possible exception of L. schreiberi, all the species of the family Lacertidae described to date appear to share homologous Z chromosomes, which date back to the last common ancestor of the whole group. We provide conclusive evidence that L. schreiberi should no longer be considered an exception to this rule, and demonstrate that the loss of microchromosomes in Iberolacerta was produced by their fusion to a middle-sized chromosome. Furthermore, we show that the multiple sex-chromosome system of the Pyrenean species of Iberolacerta originated from the fusion of the ancestral W chromosome with one of the shortest autosomes, and provide additional evidence of the fast evolution of DNA sequences linked to the W chromosome in Lacertini.

Evaluation of the pan-class I phosphoinositide 3-kinase (PI3K) inhibitor copanlisib in the Pediatric Preclinical Testing Consortium in vivo models of osteosarcoma.

Copanlisib is a pan-class I phosphoinositide 3-kinase (PI3K) inhibitor, with activity against all four PI3K class I isoforms (PI3Kα, PI3Kß, PI3Kγ, and PI3Kδ). Whole-genome and RNA sequencing data have revealed several PI3K aberrations in osteosarcoma tumor samples. The in vivo anticancer effects of copanlisib were assessed in a panel of six osteosarcoma models. Copanlisib induced prolonged event-free survival in five of six osteosarcoma models; however, all models demonstrated progressive disease suggesting minimal activity. While copanlisib did not result in tumor regression, more data are needed to fully explore the role of the PI3K pathway in the pathogenesis of osteosarcoma.

In vivo activity of the dual PI3Kδ and PI3Kγ inhibitor duvelisib against pediatric acute lymphoblastic leukemia xenografts.

BACKGROUND: Acute lymphoblastic leukemia (ALL) remains one of the most common causes of cancer-related mortality in children. Phosphoinositide 3-kinases (PI3Ks) are a family of lipid kinases, and aberrations in the PI3K pathway are associated with several hematological malignancies, including ALL. Duvelisib (Copiktra) is an orally available, small molecule dual inhibitor of PI3Kδ and PI3Kγ, that is Food and Drug Administration (FDA) approved for the treatment of relapsed/refractory chronic lymphocytic leukemia and small lymphocytic lymphoma. Here, we report the efficacy of duvelisib against a panel of pediatric ALL patient-derived xenografts (PDXs). PROCEDURES: Thirty PDXs were selected for a single mouse trial based on PI3Kδ (PIK3CD) and PI3Kγ (PIK3CG) expression and mutational status. PDXs were grown orthotopically in NSG (NOD.Cg-Prkdcscid IL2rgtm1Wjl /SzJAusb) mice, and engraftment was evaluated by enumerating the proportion of human versus mouse CD45+ cells (%huCD45+ ) in the peripheral blood. Treatment commenced when the %huCD45+ reached greater than or equal to 1%, and events were predefined as %huCD45+ greater than or equal to 25% or leukemia-related morbidity. Duvelisib was administered per oral (50 mg/kg, twice daily for 28 days). Drug efficacy was assessed by event-free survival and stringent objective response measures. RESULTS: PI3Kδ and PI3Kγ mRNA expression was significantly higher in B-lineage than T-lineage ALL PDXs (p-values <.0001). Duvelisib was well-tolerated and reduced leukemia cells in the peripheral blood in four PDXs, but with only one objective response. There was no obvious relationship between duvelisib efficacy and PI3Kδ or PI3Kγ expression or mutation status, nor was the in vivo response to duvelisib subtype dependent. CONCLUSIONS: Duvelisib demonstrated limited in vivo activity against ALL PDXs.

In vivo activity of the dual SYK/FLT3 inhibitor TAK-659 against pediatric acute lymphoblastic leukemia xenografts.

BACKGROUND: While children with acute lymphoblastic leukemia (ALL) experience close to a 90% likelihood of cure, the outcome for certain high-risk pediatric ALL subtypes remains dismal. Spleen tyrosine kinase (SYK) is a prominent cytosolic nonreceptor tyrosine kinase in pediatric B-lineage ALL (B-ALL). Activating mutations or overexpression of Fms-related receptor tyrosine kinase 3 (FLT3) are associated with poor outcome in hematological malignancies. TAK-659 (mivavotinib) is a dual SYK/FLT3 reversible inhibitor, which has been clinically evaluated in several other hematological malignancies. Here, we investigate the in vivo efficacy of TAK-659 against pediatric ALL patient-derived xenografts (PDXs). METHODS: SYK and FLT3 mRNA expression was quantified by RNA-seq. PDX engraftment and drug responses in NSG mice were evaluated by enumerating the proportion of human CD45+ cells (%huCD45+ ) in the peripheral blood. TAK-659 was administered per oral at 60 mg/kg daily for 21 days. Events were defined as %huCD45+ ≥ 25%. In addition, mice were humanely killed to assess leukemia infiltration in the spleen and bone marrow (BM). Drug efficacy was assessed by event-free survival and stringent objective response measures. RESULTS: FLT3 and SYK mRNA expression was significantly higher in B-lineage compared with T-lineage PDXs. TAK-659 was well tolerated and significantly prolonged the time to event in six out of eight PDXs tested. However, only one PDX achieved an objective response. The minimum mean %huCD45+ was significantly reduced in five out of eight PDXs in TAK-659-treated mice compared with vehicle controls. CONCLUSIONS: TAK-659 exhibited low to moderate single-agent in vivo activity against pediatric ALL PDXs representative of diverse subtypes.

Access to Assisted Reproductive Technologies in Australia: Time for Legislative Change in Queensland and the Northern Territory to Remove the Ability to Discriminate Based on Relationship Status or Sexuality.

This article examines legislative provisions in Queensland and the Northern Territory, which allow for assisted reproductive technology (ART) service providers to discriminate against people based on their relationship status and/or sexuality. We provide several arguments that add weight to the recent proposal of the Queensland Human Rights Commission that the relevant section of the Anti-Discrimination Act 1991 (Qld) be repealed, and extend our arguments to the Northern Territory. The provisions in both jurisdictions are out of sync with key legal developments in the rest of Australia, do not accord with societal views, and are potentially invalid due to federal law. Further, the Queensland provision is potentially incompatible with the Human Rights Act 2019 (Qld). Although currently ART service providers do not appear to discriminate based on relationship status or sexuality, the current legislative framework leaves open the potential to do so, without an avenue for those impacted to challenge it in law. We conclude such provisions should be repealed.

THE REQUIREMENT FOR TRANS AND GENDER DIVERSE YOUTH TO SEEK COURT APPROVAL FOR THE COMMENCEMENT OF HORMONE TREATMENT: A COMPARISON OF AUSTRALIAN JURISPRUDENCE WITH THE ENGLISH DECISION IN BELL.

This article outlines the Australian legal position relevant to minors and the commencement of hormone treatment for Gender Dysphoria (GD). It traces the significant Australian legal developments in this field and compares the Australian jurisprudence with recent English caselaw. In Quincy Bell and Mrs A v The Tavistock and Portman NHS Foundation Trust and Ors, the English High Court held that minors below 16 years are not likely to have the requisite competency to lawfully consent to the commencement of puberty suppressing drugs. The Court of Appeal subsequently overturned this decision, but there are important aspects of the High Court's reasoning that warrant further analysis, particularly some of the underlying reasoning about the nature of GD as a condition and its treatment. This article highlights several common themes when comparing the High Court's reasoning in Bell with Australian jurisprudence and highlights how the Australian position has advanced significantly since the first Australian cases in this field were decided. This comparison shows that the Australian perspective is important in demonstrating how judicial views can advance over time alongside a deeper understanding of GD, its treatment, and the broader impact of a requirement to involve the court in such cases. It is concluded that the Australian perspective should be considered in future English cases.

Evaluation of an EZH2 inhibitor in patient-derived orthotopic xenograft models of pediatric brain tumors alone and in combination with chemo- and radiation therapies.

Brain tumors are the leading cause of cancer-related death in children. Tazemetostat is an FDA-approved enhancer of zeste homolog (EZH2) inhibitor. To determine its role in difficult-to-treat pediatric brain tumors, we examined EZH2 levels in a panel of 22 PDOX models and confirmed EZH2 mRNA over-expression in 9 GBM (34.6 ± 12.7-fold) and 11 medulloblastoma models (6.2 ± 1.7 in group 3, 6.0 ± 2.4 in group 4) accompanied by elevated H3K27me3 expression. Therapeutic efficacy was evaluated in 4 models (1 GBM, 2 medulloblastomas and 1 ATRT) via systematically administered tazemetostat (250 and 400 mg/kg, gavaged, twice daily) alone and in combination with cisplatin (5 mg/kg, i.p., twice) and/or radiation (2 Gy/day × 5 days). Compared with the untreated controls, tazemetostat significantly (Pcorrected < 0.05) prolonged survival times in IC-L1115ATRT (101% at 400 mg/kg) and IC-2305GBM (32% at 250 mg/kg, 45% at 400 mg/kg) in a dose-dependent manner. The addition of tazemetostat with radiation was evaluated in 3 models, with only one [IC-1078MB (group 4)] showing a substantial, though not statistically significant, prolongation in survival compared to radiation treatment alone. Combining tazemetostat (250 mg/kg) with cisplatin was not superior to cisplatin alone in any model. Analysis of in vivo drug resistance detected predominance of EZH2-negative cells in the remnant PDOX tumors accompanied by decreased H3K27me2 and H3K27me3 expressions. These data supported the use of tazemetostat in a subset of pediatric brain tumors and suggests that EZH2-negative tumor cells may have caused therapy resistance and should be prioritized for the search of new therapeutic targets.

Comparative Studies of Karyotypes in the Cervidae Family.

The family Cervidae is the second most diverse family in the infraorder Pecora and is characterized by a striking variability in the diploid chromosome numbers among species, ranging from 6 to 70. Chromosomal rearrangements in Cervidae have been studied in detail by chromosome painting. There are many comparative cytogenetic data for both subfamilies (Cervinae and Capreolinae) based on homologies with chromosomes of cattle and Chinese muntjac. Previously it was found that interchromosomal rearrangements are the major type of rearrangements occurring in the Cervidae family. Here, we build a detailed chromosome map of a female reindeer (Rangifer tarandus, 2n = 70, Capreolinae) and a female black muntjac (Muntiacus crinifrons, 2n = 8, Cervinae) with dromedary homologies to find out what other types of rearrangements may have underlined the variability of Cervidae karyotypes. To track chromosomal rearrangements and the distribution of nucleolus organizer regions not only during Cervidae but also Pecora evolution, we summarized new data and compared them with chromosomal maps of other already studied species. We discuss changes in the pecoran ancestral karyotype in the light of new painting data. We show that intrachromosomal rearrangements in autosomes of Cervidae are more frequent than previously thought: at least 13 inversions in evolutionary breakpoint regions were detected.

The Cytogenetic Map of the Nile Crocodile (Crocodylus niloticus, Crocodylidae, Reptilia) with Fluorescence In Situ Localization of Major Repetitive DNAs.

Tandemly arranged and dispersed repetitive DNA sequences are important structural and functional elements that make up a significant portion of vertebrate genomes. Using high throughput, low coverage whole genome sequencing followed by bioinformatics analysis, we have identified seven major tandem repetitive DNAs and two fragments of LTR retrotransposons in the genome of the Nile crocodile (Crocodylus niloticus, 2n = 32). The repeats showed great variability in structure, genomic organization, and chromosomal distribution as revealed by fluorescence in situ hybridization (FISH). We found that centromeric and pericentromeric heterochromatin of C. niloticus is composed of previously described in Crocodylus siamensis CSI-HindIII and CSI-DraI repetitive sequence families, a satellite revealed in Crocodylus porosus, and additionally contains at least three previously unannotated tandem repeats. Both LTR sequences identified here belong to the ERV1 family of endogenous retroviruses. Each pericentromeric region was characterized by a diverse set of repeats, with the exception of chromosome pair 4, in which we found only one type of satellite. Only a few repeats showed non-centromeric signals in addition to their centromeric localization. Mapping of 18S-28S ribosomal RNA genes and telomeric sequences (TTAGGG)n did not demonstrate any co-localization of these sequences with revealed centromeric and pericentromeric heterochromatic blocks.

Identification of Iguania Ancestral Syntenic Blocks and Putative Sex Chromosomes in the Veiled Chameleon (Chamaeleo calyptratus, Chamaeleonidae, Iguania).

The veiled chameleon (Chamaeleo calyptratus) is a typical member of the family Chamaeleonidae and a promising object for comparative cytogenetics and genomics. The karyotype of C. calyptratus differs from the putative ancestral chameleon karyotype (2n = 36) due to a smaller chromosome number (2n = 24) resulting from multiple chromosome fusions. The homomorphic sex chromosomes of an XX/XY system were described recently using male-specific RADseq markers. However, the chromosomal pair carrying these markers was not identified. Here we obtained chromosome-specific DNA libraries of C. calyptratus by chromosome flow sorting that were assigned by FISH and sequenced. Sequence comparison with three squamate reptiles reference genomes revealed the ancestral syntenic regions in the C. calyptratus chromosomes. We demonstrated that reducing the chromosome number in the C. calyptratus karyotype occurred through two fusions between microchromosomes and four fusions between micro-and macrochromosomes. PCR-assisted mapping of a previously described Y-specific marker indicates that chromosome 5 may be the sex chromosome pair. One of the chromosome 5 conserved synteny blocks shares homology with the ancestral pleurodont X chromosome, assuming parallelism in the evolution of sex chromosomes from two basal Iguania clades (pleurodonts and acrodonts). The comparative chromosome map produced here can serve as the foundation for future genome assembly of chameleons and vertebrate-wide comparative genomic studies.

Transgender Minors and the Commencement of Hormone Treatment for Gender Dysphoria: Is Recent English Case Law Likely to Influence the Australian Legal Position?

This article considers recent English case law addressing the issue of whether court approval is required for the commencement of hormone treatment for minors with Gender Dysphoria. In particular, the decision in Bell v The Tavistock and Portman NHS Foundation Trust [2021] EWCA Civ 1363 is considered for the purpose of both distinguishing the legal framework in England from the body of Australian law on this topic, as well as considering whether the case may potentially impact on Australian law moving forward. One important aspect of the Court of Appeal's decision in Bell, which overturned the lower court's decision, is that the case clarifies how the principle of Gillick-competency should be applied in this context. The Court of Appeal held that in line with the House of Lords' reasoning in Gillick, the assessment of a minor's capacity is for the relevant treating health care professional(s) to assess rather than judges. This interpretation may potentially impact on how this principle is applied in the Australian cases relevant to minors and Gender Dysphoria, particularly those that have required an application to court in circumstances where a minor's parent(s) disagree with the conclusion of a treating clinician who has assessed their child as Gillick-competent for the purpose of consenting to hormone treatment.