The first linkage map for Australo-Papuan Treefrogs (family: Pelodryadidae) reveals the sex-determination system of the Green-eyed Treefrog (Litoria serrata).

Amphibians represent a useful taxon to study the evolution of sex determination because of their highly variable sex-determination systems. However, the sex-determination system for many amphibian families remains unknown, in part because of a lack of genomic resources. Here, using an F1 family of Green-eyed Treefrogs (Litoria serrata), we produce the first genetic linkage map for any Australo-Papuan Treefrogs (family: Pelodryadidae). The resulting linkage map contains 8662 SNPs across 13 linkage groups. Using an independent set of sexed adults, we identify a small region in linkage group 6 matching an XY sex-determination system. These results suggest Litoria serrata possesses a male heterogametic system, with a candidate sex-determination locus on linkage group 6. Furthermore, this linkage map represents the first genomic resource for Australo-Papuan Treefrogs, an ecologically diverse family of over 220 species.

The Amphibian Genomics Consortium: advancing genomic and genetic resources for amphibian research and conservation.

Amphibians represent a diverse group of tetrapods, marked by deep divergence times between their three systematic orders and families. Studying amphibian biology through the genomics lens increases our understanding of the features of this animal class and that of other terrestrial vertebrates. The need for amphibian genomic resources is more urgent than ever due to the increasing threats to this group. Amphibians are one of the most imperiled taxonomic groups, with approximately 41% of species threatened with extinction due to habitat loss, changes in land use patterns, disease, climate change, and their synergistic effects. Amphibian genomic resources have provided a better understanding of ontogenetic diversity, tissue regeneration, diverse life history and reproductive modes, antipredator strategies, and resilience and adaptive responses. They also serve as essential models for studying broad genomic traits, such as evolutionary genome expansions and contractions, as they exhibit the widest range of genome sizes among all animal taxa and possess multiple mechanisms of genetic sex determination. Despite these features, genome sequencing of amphibians has significantly lagged behind that of other vertebrates, primarily due to the challenges of assembling their large, repeat-rich genomes and the relative lack of societal support. The emergence of long-read sequencing technologies, combined with advanced molecular and computational techniques that improve scaffolding and reduce computational workloads, is now making it possible to address some of these challenges. To promote and accelerate the production and use of amphibian genomics research through international coordination and collaboration, we launched the Amphibian Genomics Consortium (AGC, https://mvs.unimelb.edu.au/amphibian-genomics-consortium) in early 2023. This burgeoning community already has more than 282 members from 41 countries. The AGC aims to leverage the diverse capabilities of its members to advance genomic resources for amphibians and bridge the implementation gap between biologists, bioinformaticians, and conservation practitioners. Here we evaluate the state of the field of amphibian genomics, highlight previous studies, present challenges to overcome, and call on the research and conservation communities to unite as part of the AGC to enable amphibian genomics research to "leap" to the next level.

Regulation of breast cancer response to chemotherapy by fibulin-1.

Doxorubicin treatment was found to augment the expression of the extracellular matrix (ECM) protein fibulin-1 in cultured human breast cancer cell lines and in MDA-MB-361 tumors grown in athymic mice. Doxorubicin was also found to augment tumor expression of the fibulin-1-binding proteins fibronectin and laminin-1. Growth of breast cancer cell lines on Matrigel, an ECM extract containing fibulin-1 and laminin-1, resulted in lower levels of doxorubicin-induced apoptosis as compared with controls. Moreover, tumors formed by injection of athymic mice with MDA-MB-361 cells mixed with Matrigel were significantly more doxorubicin resistant and displayed lower levels of apoptosis compared with those that formed in the absence of Matrigel. Monoclonal antibodies against fibulin-1 reversed Matrigel-dependent doxorubicin resistance. Furthermore, small interfering RNA-mediated suppression of fibulin-1 expression in breast cancer cells resulted in a 10-fold increase in doxorubicin sensitivity as compared with control cells. Together, these findings point to a role for fibulin-1 in breast cancer chemoresistance.

A new species of Phyllurus leaf-tailed gecko (Lacertilia: Carphodactylidae) from The Pinnacles, north-east Australia.

Recent surveys of rocky rainforest in the Townsville region have found additional populations of Phyllurus geckos. One of these populations was discovered at The Pinnacles, an isolated area of habitat in between the distributions of P. gulbaru and P. amnicola. Genetic and morphological data shows that this population is most similar to P. gulbaru Hoskin, Couper Schneider, 2003 but divergent in a number of traits. Here we describe this population as a new species, P. pinnaclensis sp. nov., based on genetic divergence and differences in a number of morphometric and scalation traits from other populations of Phyllurus. Phyllurus pinnaclensis sp. nov. appears to be restricted to a few small areas of deeply layered rock with associated dry rainforest. This habitat is fire-sensitive and increased frequency and intensity of fires (due to late season burns and high fuel loads of invasive grasses) threatens to reduce and fragment these dry rainforest patches. Other threats include potential future invasion of the habitat by introduced Asian House Geckos (Hemidactylus frenatus Duméril Bibron, 1836) and illegal collecting. Given the very small and fragmented distribution and potential reduction in habitat area due to fire, P. pinnaclensis sp. nov. warrants a Critically Endangered listing. Resolving the distributional change of dry rainforest in the Townsville region in recent decades, particularly in regards to fire, is key to resolving the status of this and other locally threatened taxa that depend on this habitat.

Radiation effects on development of HER2-positive breast carcinomas.

PURPOSE: Neither hormone-related nor genetics risk factors have been associated with the development of highly proliferative HER2-positive breast carcinomas. Because the majority of HER2-positive tumors present the amplification of the oncogene, we asked whether genomic instability triggered by irradiation might be involved in the induction of HER2-overexpressing breast carcinomas. EXPERIMENTAL DESIGN: Sixty-six infiltrating breast carcinomas from patients treated with radiation therapy for Hodgkin's lymphoma or other pediatric solid tumors and a control series of 61 consecutive sporadic breast tumors were analyzed by immunohistochemistry for HER2 expression with HercepTest. A panel of antibodies against estrogen receptor, progesterone receptor, c-kit, cytokeratin 5/6, p53, and ki67 antigen was also used to identify differentiation subsets and molecular characteristics of the analyzed breast carcinomas. RESULTS: Although no differences between the two tumor series were found with respect to HER2 expression scored 2+ and 3+, the percentage of 3+ HER2-positive tumors was significantly higher in patients irradiated during breast maturation compared with patients irradiated after breast maturation (35.3% versus 12.5%, P = 0.046). In the latter group, 52.5% of the breast carcinomas showed basal-like differentiation (estrogen receptor, progesterone receptor, and HER2 negative) versus only 5.9% in the group irradiated during breast development (P < 0.0001). Analysis adjusted for age confirmed the significant increase in basal-like tumor development in patients irradiated within 4 years of menarche, but also showed that the differences between patients irradiated before and after puberty in HER2 3+ tumor frequencies are due to age-related differences in HER2 3+ tumor onset. CONCLUSION: Together, our data indicate that the development of HER2-positive tumors correlates with timing rather than type of carcinogenic hits and provide clear evidence that radiation is a risk factor for breast carcinomas showing basal-like differentiation.