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Snakebite envenoming is a serious and neglected tropical disease that kills ~100,000 people annually. High-quality, genome-enabled comprehensive characterization of toxin genes will facilitate development of effective humanized recombinant antivenom. We report a de novo near-chromosomal genome assembly of Naja naja , the Indian cobra, a highly venomous, medically important snake. Our assembly has a scaffold N50 of 223.35 Mb, with 19 scaffolds containing 95% of the genome. Of the 23,248 predicted protein-coding genes, 12,346 venom-gland-expressed genes constitute the ‘venom-ome’ and this included 139 genes from 33 toxin families. Among the 139 toxin genes were 19 ‘venom-ome-specific toxins’ (VSTs) that showed venom-gland-specific expression, and these probably encode the minimal core venom effector proteins. Synthetic venom reconstituted through recombinant VST expression will aid in the rapid development of safe and effective synthetic antivenom. Additionally, our genome could serve as a reference for snake genomes, support evolutionary studies and enable venom-driven drug discovery. Analysis of a near-chromosomal genome assembly and transcriptome profiling of the Indian cobra identifies genes expressed in the venom glands. These data should help develop a new antivenom.

We generated single haplotype assemblies from a hinny hybrid which significantly improved the gapless contiguity for horse and donkey autosomal genomes and the X chromosomes. We added over 15 Mb of missing sequence to both X chromosomes, 60 Mb to donkey autosomes and corrected numerous errors in donkey and some in horse reference genomes. We resolved functionally important X-linked repeats: the DXZ4 macrosatellite and ampliconic Equine Testis Specific Transcript Y7 ( ETSTY7 ). We pinpointed the location of the pseudoautosomal boundaries (PAB) and determined the size of the horse (1.8 Mb) and donkey (1.88 Mb) pseudoautosomal regions (PARs). We discovered distinct differences in horse and donkey PABs: a testis-expressed gene, XKR3Y , spans horse PAB with exons1–2 located in Y and exon3 in the X–Y PAR, whereas the donkey XKR3Y is Y-specific. DXZ4 had a similar ~ 8 kb monomer in both species with 10 copies in horse and 20 in donkey. We assigned hundreds of copies of ETSTY7 , a sequence horizontally transferred from Parascaris and massively amplified in equids, to horse and donkey X chromosomes and three autosomes. The findings and products contribute to molecular studies of equid biology and advance research on X-linked conditions, sex chromosome regulation and evolution in equids.

LINE-1 is an active transposable element encoding proteins capable of inserting host gene retrocopies, resulting in retro-copy number variants (retroCNVs) between individuals. Here, we performed retroCNV discovery using 86 equids and identified 437 retrocopy insertions. Only 5 retroCNVs were shared between horses and other equids, indicating that the majority of retroCNVs inserted after the species diverged. A large number (17–35 copies) of segmentally duplicated Ligand Dependent Nuclear Receptor Corepressor Like ( LCORL ) retrocopies were present in all equids but absent from other extant perissodactyls. The majority of LCORL transcripts in horses and donkeys originate from the retrocopies. The initial LCORL retrotransposition occurred 18 million years ago (17–19 95% CI), which is coincident with the increase in body size, reduction in digit number, and changes in dentition that characterized equid evolution. Evolutionary conservation of the LCORL retrocopy segmental amplification in the Equidae family, high expression levels and the ancient timeline for LCORL retrotransposition support a functional role for this structural variant.

Application of next-generation sequencing (NGS) to DNA metabarcoding can greatly increase the understanding of predator–prey dynamics and the conflict between wildlife and humans, but remains underutilized for carnivores such as the threatened snow leopard (Panthera uncia). To date, this technique was hindered by the difficulty in discerning closely related caprines (Caprinae). We identified a segment of mitochondrial cytochrome c oxidase subunit 1 (MT-CO1) to differentiate these prey, and used this marker in tandem with a portion of mitochondrial 12S rRNA (MT-RNR1) to determine dietary items in 165 genetically confirmed snow leopard scats from four range countries. Identified prey species consisted of ten medium to large mammals, three small mammals, and two birds. The dominant prey consumed varied by country, with markhor (Capra falconeri) most prevalent in Pakistan, Siberian ibex (C. sibirica) in Mongolia and Kyrgyzstan, and blue sheep (Pseudois nayaur) in China. Livestock comprised 31% of diet occurrences from Pakistan and 15% from Mongolia. Domestic livestock included goat (C. aegagrus hircus), sheep (Ovis aries), bovids (Bos taurus, B. grunniens, and potentially hybrids), and horse (Equus caballus). Protection and management of regionally specific wild prey is crucial for sustaining snow leopard populations, although overall dietary breadth suggests that snow leopards may exploit other species if necessary, including livestock. Additional sampling efforts across seasons, years, regions, and areas with varying degrees of livestock depredation are needed. MT-CO1 in conjunction with MT-RNR1 can be applied to other carnivore diet studies, making it an important tool for conservation and research, particularly in ecosystems with pastoral communities.

A 10-year-old intact female Chinese Crested dog was presented for evaluation and further diagnostics due to persistent symptoms of vulvar swelling, vaginal discharge, and an 8-year history of acyclicity. At presentation, generalized hyperpigmentation and truncal alopecia were identified, with no aberrations of the female phenotype. Vaginal cytology confirmed the influence of estrogen at multiple veterinary visits, and hormonal screening of progesterone and anti-Mullerian hormone indicated gonadal presence. Based on findings from abdominal laparotomy and gonadectomy, the tissue was submitted for histopathology. Histopathologic evaluation identified the gonads to be abnormal testes containing multiple Sertoli and interstitial (Leydig) cell tumors. The histopathologic diagnosis of testes and concurrent normal external female phenotype in the patient lead to a diagnosis of a disorder of sexual development (DSD). Karyotype evaluation by conventional and molecular analysis revealed a two cell line chimeric pattern of 78,XX (80%) and 78,XY (20%) among blood leukocytes, as well as a positive PCR test for the Y-linked SRY gene. Cytogenetic analysis of skin fibroblasts revealed the presence of 78,XX cells exclusively, and PCR tests for the Y-linked SRY gene were negative in the hair and skin samples. These results are consistent with an XX/XY blood chimerism. This is one of the few case reports of a canine with the diagnosis of leukocyte chimerism with normal female phenotypic external genitalia. This case illustrates a distinct presentation for hormonally active Sertoli cell tumorigenesis and demonstrates surgery as a curative treatment option for clinically affected patients.

Disorders of sex development (DSD) and reproduction are not uncommon among horses, though knowledge about their molecular causes is sparse. Here we characterized a ~200 kb homozygous deletion in chromosome 29 at 29.7–29.9 Mb. The region contains AKR1C genes which function as ketosteroid reductases in steroid hormone biosynthesis, including androgens and estrogens. Mutations in AKR1C genes are associated with human DSDs. Deletion boundaries, sequence properties and gene content were studied by PCR and whole genome sequencing of select deletion homozygotes and control animals. Deletion analysis by PCR in 940 horses, including 622 with DSDs and reproductive problems and 318 phenotypically normal controls, detected 67 deletion homozygotes of which 79% were developmentally or reproductively abnormal. Altogether, 8–9% of all abnormal horses were homozygous for the deletion, with the highest incidence (9.4%) among cryptorchids. The deletion was found in ~4% of our phenotypically normal cohort, ~1% of global warmblood horses and ponies, and ~7% of draught breeds of general horse population as retrieved from published data. Based on the abnormal phenotype of the carriers, the functionally relevant gene content, and the low incidence in general population, we consider the deletion in chromosome 29 as a risk factor for equine DSDs and reproductive disorders.

The unique evolutionary dynamics and complex structure make the Y chromosome the most diverse and least understood region in the mammalian genome, despite its undisputable role in sex determination, development, and male fertility. Here we present the first contig-level annotated draft assembly for the alpaca (Vicugna pacos) Y chromosome based on hybrid assembly of short- and long-read sequence data of flow-sorted Y. The latter was also used for cDNA selection providing Y-enriched testis transcriptome for annotation. The final assembly of 8.22 Mb comprised 4.5 Mb of male specific Y (MSY) and 3.7 Mb of the pseudoautosomal region. In MSY, we annotated 15 X-degenerate genes and two novel transcripts, but no transposed sequences. Two MSY genes, HSFY and RBMY, are multicopy. The pseudoautosomal boundary is located between SHROOM2 and HSFY. Comparative analysis shows that the small and cytogenetically distinct alpaca Y shares most of MSY sequences with the larger dromedary and Bactrian camel Y chromosomes. Most of alpaca X-degenerate genes are also shared with other mammalian MSYs, though WWC3Y is Y-specific only in alpaca/camels and the horse. The partial alpaca Y assembly is a starting point for further expansion and will have applications in the study of camelid populations and male biology.

Understanding landscape connectivity and population genetic parameters is imperative for threatened species management. However, such information is lacking for the snow leopard (Panthera uncia). This study sought to explore hierarchical snow leopard gene flow patterns and drivers of genetic structure in Mongolia and China. A total of 97 individuals from across Mongolia and from the north-eastern edge of the Qinghai-Tibetan Plateau in Gansu Province to the middle of Qinghai Province in China were genotyped across 24 microsatellite loci. Distance-based frameworks were used to determine a landscape scenario best explaining observed genetic structure. Spatial and non-spatial methods were used to investigate fine-scale autocorrelation and similarity patterns as well as genetic structure and admixture. A genetic macro-division between populations in China and Mongolia was observed, suggesting that the Gobi Desert is a substantial barrier to gene flow. However, admixture and support for a resistance-based mode of isolation suggests connective routes that could facilitate movement. Populations in Mongolia had greater connectivity, indicative of more continuous habitat. Drivers of genetic structure in China were difficult to discern, and fine-scale sampling is needed. This study elucidates snow leopard landscape connectivity and helps to prioritize conservation areas. Although contact zones may have existed and occasional crossings can occur, establishing corridors to connect these areas should not be a priority. Focus should be placed on maintaining the relatively high connectivity for snow leopard populations within Mongolia and increasing research efforts in China.

LINE-1 is an active transposable element encoding proteins capable of inserting host gene retrocopies, resulting in retro-copy number variants (retroCNVs) between individuals. Here, we performed retroCNV discovery using 86 equids and identified 437 retrocopy insertions. Only 5 retroCNVs were shared between horses and other equids, indicating that the majority of retroCNVs inserted after the species diverged. A large number (17–35 copies) of segmentally duplicated Ligand Dependent Nuclear Receptor Corepressor Like (LCORL) retrocopies were present in all equids but absent from other extant perissodactyls. The majority of LCORL transcripts in horses and donkeys originate from the retrocopies. The initial LCORL retrotransposition occurred 18 million years ago (17–19 95% CI), which is coincident with the increase in body size, reduction in digit number, and changes in dentition that characterized equid evolution. Evolutionary conservation of the LCORL retrocopy segmental amplification in the Equidae family, high expression levels and the ancient timeline for LCORL retrotransposition support a functional role for this structural variant.

Laminitis is characterized by the separation of the phalanx and the hoof wall. It can be induced in horses by ingesting high amounts of non-structural carbohydrates (NSC), which changes the hindgut microflora. However, fecal bacteria may not be representative of the cecum. In addition, in horses results from more recent sequencers (Illumina) have never been compared to previously used sequencers (454). To determine if there are functional differences alpha and beta-diversity, core biomes, and shifts in hindgut bacteria in response to NSC were compared between fecal and cecal communities and the MiSeq and 454 method. The results suggest that MiSeq is superior to the 454 due to greater number of reads per cost. The method had a greater effect on the diversity than the sample origin. Fecal microflora exhibited more substantial shifts than the cecum. It is hypothesized this is due to the downstream migration of lactic acid and VFAs.