Atrial septal defects in Florida panthers

Give and Take: Effects of Genetic Admixture on Mutation Load in Endangered Florida Panthers

Genetic admixture is a biological event inherent to genetic rescue programs aimed at the long-term conservation of endangered wildlife. Although the success of such programs can be measured by the increase in genetic diversity and fitness of subsequent admixed individuals, predictions supporting admixture costs to fitness due to the introduction of novel deleterious alleles are necessary. Here, we analyzed nonsynonymous variation from conserved genes to quantify and compare levels of mutation load (i.e., proportion of deleterious alleles and genotypes carrying these alleles) among endangered Florida panthers and non-endangered Texas pumas. Specifically, we used canonical (i.e., non-admixed) Florida panthers, Texas pumas, and F1 (canonical Florida x Texas) panthers dating from a genetic rescue program and Everglades National Park panthers with Central American ancestry resulting from an earlier admixture event. We found neither genetic drift nor selection significantly reduced overall proportions of deleterious alleles in the severely bottlenecked canonical Florida panthers. Nevertheless, the deleterious alleles identified were distributed into a disproportionately high number of homozygous genotypes due to close inbreeding in this group. Conversely, admixed Florida panthers (either with Texas or Central American ancestry) presented reduced levels of homozygous genotypes carrying deleterious alleles but increased levels of heterozygous genotypes carrying these variants relative to canonical Florida panthers. Although admixture is likely to alleviate the load of standing deleterious variation present in homozygous genotypes, our results suggest introduced novel deleterious alleles (temporarily present in heterozygous state) in genetically rescued populations could potentially be expressed in subsequent generations if their effective sizes remain small.

De Novo Assembly and Annotation from Parental and F1 Puma Genomes of the Florida Panther Genetic Restoration Program

In the mid-1990s, the population size of Florida panthers became so small that many individuals manifested traits associated with inbreeding depression (e.g., heart defects, cryptorchidism, high pathogen-parasite load). To mitigate these effects, pumas from Texas were introduced into South Florida to augment genetic variation in Florida panthers. In this study, we report a de novo puma genome assembly and annotation after resequencing 10 individual genomes from partial Florida-Texas-F₁ trios. The final genome assembly consisted of ∼2.6 Gb and 20,561 functionally annotated protein-coding genes. Foremost, expanded gene families were associated with neuronal and embryological development, whereas contracted gene families were associated with olfactory receptors. Despite the latter, we characterized 17 positively selected genes related to the refinement of multiple sensory perceptions, most notably to visual capabilities. Furthermore, genes under positive selection were enriched for the targeting of proteins to the endoplasmic reticulum, degradation of mRNAs, and transcription of viral genomes. Nearly half (48.5%) of ∼6.2 million SNPs analyzed in the total sample set contained putative unique Texas alleles. Most of these alleles were likely inherited to subsequent F₁ Florida panthers, as these individuals manifested a threefold increase in observed heterozygosity with respect to their immediate, canonical Florida panther predecessors. Demographic simulations were consistent with a recent colonization event in North America by a small number of founders from South America during the last glacial period. In conclusion, we provide an extensive set of genomic resources for pumas and elucidate the genomic effects of genetic rescue on this iconic conservation success story.

Atrial septal defect in a Korean wild raccoon dog

An approximately two-year-old, male 6.1 kg body weight, Korean wild raccoon dog (Nyctereutes procyonoides koreensis) was captured by the wildlife medical rescue center of Kangwon National University. Upon physical examination, the heart rate was 87 beats per min and there were no clinical signs. The hematological, and blood biochemical profiles revealed no remarkable findings; however, thoracic radiographs showed cardiac enlargement, especially in the right atrium. On electrocardiogram, sinus node dysfunction and bradyarrhythmia were revealed. Echocardiography showed a left-to-right shunting atrial septal defect. Based on these findings, this Korean wild raccoon dog was diagnosed with atrial septal defect. This is the rare case report of atrial septal defect in wildlife.

Evolutionary and Functional Mitogenomics Associated With the Genetic Restoration of the Florida Panther

Florida panthers are endangered pumas that currently persist in reduced patches of habitat in South Florida, USA. We performed mitogenome reference-based assemblies for most parental lines of the admixed Florida panthers that resulted from the introduction of female Texas pumas into South Florida in 1995. With the addition of 2 puma mitogenomes, we characterized 174 single nucleotide polymorphisms (SNPs) across 12 individuals. We defined 5 haplotypes (Pco1-Pco5), one of which (Pco1) had a geographic origin exclusive to Costa Rica and Panama and was possibly introduced into the Everglades National Park, Florida, prior to 1995. Haplotype Pco2 was native to Florida. Haplotypes Pco3 and Pco4 were exclusive to Texas, whereas haplotype Pco5 had an undetermined geographic origin. Phylogenetic inference suggests that haplotypes Pco1-Pco4 diverged ~202000 (95% HPDI = 83000-345000) years ago and that haplotypes Pco2-Pco4 diverged ~61000 (95% HPDI = 9000-127000) years ago. These results are congruent with a south-to-north continental expansion and with a recent North American colonization by pumas. Furthermore, pumas may have migrated from Texas to Florida no earlier than ~44000 (95% HPDI = 2000-98000) years ago. Synonymous mutations presented a greater mean substitution rate than other mitochondrial functional regions: nonsynonymous mutations, tRNAs, rRNAs, and control region. Similarly, all protein-coding genes were under predominant negative selection constraints. We directly and indirectly assessed the presence of potential deleterious SNPs in the ND2 and ND5 genes in Florida panthers prior to and as a consequence of the introduction of Texas pumas. Screenings for such variants are recommended in extant Florida panthers.

Genetic restoration of the Florida panther

The rediscovery of remnant Florida panthers (Puma concolor coryi) in southern Florida swamplands prompted a program to protect and stabilize the population. In 1995, conservation managers translocated eight female pumas (P. c. stanleyana) from Texas to increase depleted genetic diversity, improve population numbers, and reverse indications of inbreeding depression. We have assessed the demographic, population-genetic, and biomedical consequences of this restoration experiment and show that panther numbers increased threefold, genetic heterozygosity doubled, survival and fitness measures improved, and inbreeding correlates declined significantly. Although these results are encouraging, continued habitat loss, persistent inbreeding, infectious agents, and possible habitat saturation pose new dilemmas. This intensive management program illustrates the challenges of maintaining populations of large predators worldwide.

Dysplastic tracheae in eight blue duikers (Cephalophus monticola) from Bioko, Equatorial Guinea

Nine blue duikers (Cephalophus monticola), purchased in the Malabo bushmeat market, were necropsied. Eight of the nine animals were found to have dysplastic tracheas, characterized by lateral apposition of tracheal rings, entrapment of the trachealis muscle and annular ligaments, and bunching of the tracheal epithelium. Communications with zoologic pathologists and a thorough search of the veterinary literature have not uncovered a single case of this pathologic finding. As such, this finding may represent an evolutionary marker indicative of a bottleneck that may have occurred in the history of this species of duiker, endemic to the island of Bioko, in the Gulf of Benin.

Causes of mortality in the Florida panther (Felis concolor coryi)

Panthers necropsied at the University of Florida ranged between 2 weeks and 14 years of age; there were 38 males and 17 females in the cohort. Main categories of causes of death included trauma inflicted from either vehicular collisions (43%) or territorial fights (16%). Specific endogenous diseases involved the respiratory system in 13%, the urinary system in 4%, and the central nervous system in 2%. Ostium secundum atrial septal defects (ASD) were diagnosed in 11% of the panthers necropsied. Seventeen (54%) of the 38 male panthers had either unilateral or bilateral cryptorchidism. Cause of death remained undetermined in 11% of the total cohort.

Bilateral eyelid agenesis repair in a captive Texas cougar

Bilateral eyelid agenesis was presented with multiple ocular anomalies in a captive Texas cougar (Felis concolor). Corneal exposure resulted in substantial keratoconjunctivitis and blepharospasm. Bilateral inferopapillary fundic colobomas, persistent pupillary membranes, and an atypical iris coloboma OD were present. Surgical repair with a rotational pedicle flap resulted in functionally effective eyelids. Trichiasis was later treated with cryotherapy. Eyelid agenesis is reported infrequently in domestic cats and among large felids has only been reported in the snow leopard.