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1.
Animals (Basel) ; 12(19)2022 Oct 03.
Article in English | MEDLINE | ID: mdl-36230401

ABSTRACT

Lizards within the Iguana iguana species complex are among the most common reptilian pets, with the widest natural geographic range among iguanids. Deep phylogenetic divergence distinguishes multiple mitochondrial clades, and several taxonomic changes have recently been proposed. These small populations, typically island endemics, are threatened by numerous factors, including the international pet trade. Recent investigations reveal the absence of required CITES permits for lawful export of animals, providing evidence of ongoing illegal trade. Additional monitoring of trade in iguanas can be achieved through the application of forensic molecular techniques. In this study, two captive melanistic iguanas were genotyped for molecular markers for which geographic distributions of alleles have been established. Mitochondrial sequencing indicates that both animals carry a haplotype known to originate from the islands of Saba and Montserrat, populations taxonomically proposed to be Iguana melanoderma. Genotypes at 15 microsatellite loci are equally consistent with this origin, given the results of a principal component analysis. This first forensic genetic assessment within the extensive I. iguana pet trade highlights the presence of illegal activity. The need for additional forensic assessments of pet-trade iguanas is evident, especially given that their value is driven by variety and rarity, which is further intensified by recent taxonomic changes.

2.
Medicine (Baltimore) ; 101(38): e30709, 2022 Sep 23.
Article in English | MEDLINE | ID: mdl-36197252

ABSTRACT

Bronchial thermoplasty (BT) is one of the novel approved modalities in treating severe asthmatics to overcome their exacerbating symptoms such as increased anxiety. The purpose of this study was to evaluate anxiety level among severe asthmatics while undergoing BT procedure. This was an observational study where subjects self-evaluated their overall anxiety level using the burns anxiety inventory (BAI) questionnaire at baseline and prior to each of three BT treatments (broncho thermoplasty procedure 1, broncho thermoplasty procedure 2, and broncho thermoplasty procedure 3). The BAI questionnaire consisted of three different categories with each category having specific symptoms. Categories were grouped as: Anxious feelings, Anxious thoughts, and Physical symptoms. Subjects' Asthma Control Tests were also collected for analysis before and after the BT procedure. A total of 17 subjects with a mean age of 55.9 ±â€…14.5 years participated in the study. Fifty three percent were females (n = 9) and 41.2% (n = 7) were on prescribed anxiety medications. There was a significant drop in the patients' overall BAI anxiety level over time, P < .0001, in Anxious feelings (P = .0001), anxious thoughts (P = .001), and physical symptoms (P = .025). When analyzing the change in anxiety level among those who were not on prescribed anxiety medications, significant drop in overall anxiety level and in the subcategories were also noted. (P < .05). In addition, ACT scores showed a significant improvement (post vs pre) (18.5 ±â€…4.0 vs 13.3 ±â€…6.3, P = .03; Cohen's d = 0.73). This study shows the effectiveness of BT in decreasing severe asthmatic anxiety levels from baseline to last BT treatment and this benefit was mostly noted in those who were not on any anxiety medications. A limitation of this study is that all subjects were recruited from a single center. Therefore, to further validate the study findings, a multi-center study needs to be conducted with a larger sample size.


Subject(s)
Asthma , Bronchial Thermoplasty , Adult , Aged , Anxiety/etiology , Asthma/drug therapy , Bronchial Thermoplasty/methods , Female , Humans , Male , Middle Aged , Surveys and Questionnaires
3.
Mol Genet Genomics ; 297(5): 1329-1342, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35786764

ABSTRACT

Microsatellites, also known as short tandem repeats (STRs), have long been considered non-functional, neutrally evolving regions of the genome. Recent findings suggest that they can function as drivers of rapid adaptive evolution. Previous work on the common sunflower identified 479 transcribed microsatellites where allele length significantly correlates with gene expression (eSTRs) in a stepwise manner. Here, a population genetic approach is used to test whether eSTR allele length variation is under selection. Genotypic variation among and within populations at 13 eSTRs was compared with that at 19 anonymous microsatellites in 672 individuals from 17 natural populations of sunflower from across a cline running from Saskatchewan to Oklahoma (distance of approximately 1600 km). Expected heterozygosity, allelic richness, and allelic diversity were significantly lower at eSTRs, a pattern consistent with higher relative rates of purifying selection. Further, an analysis of variation in microsatellite allele lengths (lnRV), and heterozygosities (lnRH), indicate recent selective sweeps at the eSTRs. Mean microsatellite allele lengths at four eSTRs within populations are significantly correlated with latitude consistent with the predictions of the tuning-knob model which predicts stepwise relationships between microsatellite allele length and phenotypes. This finding suggests that shorter or longer alleles at eSTRs may be favored in climatic extremes. Collectively, our results imply that eSTRs are likely under selection and that they may be playing a role in facilitating local adaptation across a well-defined cline in the common sunflower.


Subject(s)
Helianthus , Alleles , Genetic Variation , Genetics, Population , Genotype , Microsatellite Repeats , Selection, Genetic
4.
Mol Phylogenet Evol ; 174: 107548, 2022 09.
Article in English | MEDLINE | ID: mdl-35690377

ABSTRACT

The genus Cyclura includes nine extant species and six subspecies of West Indian Rock Iguanas and is one of the most imperiled genera of squamate reptiles globally. An understanding of species diversity, evolutionary relationships, diversification, and historical biogeography in this group is crucial for implementing sound long-term conservation strategies. We collected DNA samples from 1 to 10 individuals per taxon from all Cyclura taxa (n = 70 ingroup individuals), focusing where possible on incorporating individuals from different populations of each species. We also collected 1-2 individuals from each of seven outgroup species of iguanas (Iguana delicatissima; five Ctenosaura species) and Anolis sagrei (n = 12 total outgroup individuals). We used targeted genomic sequence capture to isolate and to sequence 1,872 loci comprising of 687,308 base pairs (bp) from each of the 82 individuals from across the nuclear genome. We extracted mitochondrial reads and assembled and annotated mitogenomes for all Cyclura taxa plus outgroup species. We present well-supported phylogenomic gene tree/species tree analyses for all extant species of Cyclura using ASTRAL-III, SVDQuartets, and StarBEAST2 methods, and discuss the taxonomic, biogeographic, and conservation implications of these data. We find a most recent common ancestor of the genus 9.91 million years ago. The earliest divergence within Cyclura separates C. pinguis from a clade comprising all other Cyclura. Within the latter group, a clade comprising C. carinata from the southern Lucayan Islands and C. ricordii from Hispaniola is the sister taxon to a clade comprising the other Cyclura. Among the other Cyclura, the species C. cornuta and C. stejnegeri (from Hispaniola and Isla Mona) form the sister taxon to a clade of species from Jamaica (C. collei), Cuba and Cayman Islands (C. nubila and C. lewisi), and the eastern (C. rileyi) and western (C. cychlura) Lucayan Islands. Cyclura cychlura and C. rileyi form a clade whose sister taxa are C. nubila and C. lewisi. Cyclura collei is the sister taxon to these four species combined.


Subject(s)
Iguanas , Lizards , Animals , Cuba , Humans , Iguanas/genetics , Lizards/genetics , Phylogeny , Sequence Analysis, DNA , West Indies
5.
J Hered ; 112(7): 590-601, 2021 12 17.
Article in English | MEDLINE | ID: mdl-34612500

ABSTRACT

Three subspecies of Northern Bahamian Rock Iguanas, Cyclura cychlura, are currently recognized: C. c. cychlura, restricted to Andros Island, and C. c. figginsi and C. c. inornata, native to the Exuma Island chain. Populations on Andros are genetically distinct from Exuma Island populations, yet genetic divergence among populations in the Exumas is inconsistent with the 2 currently recognized subspecies from those islands. The potential consequences of this discrepancy might include the recognition of a single subspecies throughout the Exumas rather than 2. That inference also ignores evidence that populations of C. cychlura are potentially adaptively divergent. We compared patterns of population relatedness in a three-tiered host-parasite system: C. cychlura iguanas, their ticks (genus Amblyomma, preferentially parasitizing these reptiles), and Rickettsia spp. endosymbionts (within tick ectoparasites). Our results indicate that while C. c. cychlura on Andros is consistently supported as a separate clade, patterns of relatedness among populations of C. c. figginsi and C. c. inornata within the Exuma Island chain are more complex. The distribution of the hosts, different tick species, and Rickettsia spp., supports the evolutionary independence of C. c. inornata. Further, these patterns are also consistent with two independent evolutionarily significant units within C. c. figginsi. Our findings suggest coevolutionary relationships between the reptile hosts, their ectoparasites, and rickettsial organisms, suggesting local adaptation. This work also speaks to the limitations of using neutral molecular markers from a single focal taxon as the sole currency for recognizing evolutionary novelty in populations of endangered species.


Subject(s)
Iguanas , Lizards , Parasites , Animals , Genetics, Population
6.
ACS Appl Mater Interfaces ; 13(7): 9239-9251, 2021 Feb 24.
Article in English | MEDLINE | ID: mdl-33565870

ABSTRACT

Simple n-alcohols, such as 1-dodecanol, show anomalous film-forming and friction behaviors under elastohydrodynamic lubrication (EHL) conditions, as found inside bearings and gears. Using tribometer, diamond anvil cell (DAC), and differential scanning calorimetry (DSC) experiments, we show that liquid 1-dodecanol undergoes a pressure-induced solidification when entrained into EHL contacts. Different solid polymorphs are formed inside the contact depending on the temperature and pressure conditions. Surprisingly, at a moderate temperature and pressure, 1-dodecanol forms a polymorph that exhibits robust macroscale superlubricity. The DAC and DSC experiments show that superlubricity is facilitated by the formation of lamellar, hydrogen-bonded structures of hexagonally close-packed molecules, which promote interlayer sliding. This novel superlubricity mechanism is similar to that proposed for the two-dimensional materials commonly employed as solid lubricants, but it also enables the practical advantages of liquid lubricants to be maintained. When the pressure is increased, 1-dodecanol undergoes a polymorphic transformation into a phase that gives a higher friction. The DAC and DSC experiments indicate that the high-friction polymorph is an orthorhombic crystal. The polymorphic transformation pressure coincides with the onset of a dimple formation in the EHL films, revealing that the anomalous film shapes are caused by the formation of rigid orthorhombic crystals inside the contact. This is the first demonstration of a macroscale superlubricity in an EHL contact lubricated by a nonaqueous liquid that arises from bulk effects rather than tribochemical transformations at the surfaces. Since the superlubricity observed here results from phase transformations, it is continuously self-replenishing and is insensitive to surface chemistry and topology. This discovery creates the possibility of implementing superlubricity in a wide range of machine components, which would result in enormous improvements in efficiency and durability.

7.
PLoS One ; 15(8): e0236875, 2020.
Article in English | MEDLINE | ID: mdl-32813748

ABSTRACT

The Upper Palaeolithic is characterised by the appearance of iconographic expressions most often depicting animals, including anthropomorphic forms, and geometric signs. The Late Upper Palaeolithic Magdalenian saw a flourishing of such depictions, encompassing cave art, engraving of stone, bone and antler blanks and decoration of tools and weapons. Though Magdalenian settlement exists as far northwest as Britain, there is a limited range of art known from this region, possibly associated with only fleeting occupation of Britain during this period. Stone plaquettes, flat fragments of stone engraved on at least one surface, have been found in large quantities at numerous sites spanning the temporal and geographical spread of the Magdalenian, but they have been absent so far from the archaeological record of the British Isles. Between 2015 and 2018, ten fragments of stone plaquettes extensively engraved with abstract designs were uncovered at the Magdalenian site of Les Varines, Jersey, Channel Islands. In this paper, we report detailed analyses of these finds, which provide new evidence for technologies of abstract mark-making, and their significance within the lives of people on the edge of the Magdalenian world. These engraved stone fragments represent important, rare evidence of artistic expression in what is the far northern and western range of the Magdalenian and add new insight to the wider significance of dynamic practices of artistic expression during the Upper Palaeolithic.


Subject(s)
Archaeology , Art , Engraving and Engravings , Islands
8.
Mol Ecol ; 29(9): 1704-1716, 2020 05.
Article in English | MEDLINE | ID: mdl-32285554

ABSTRACT

Microsatellites are common in genomes of most eukaryotic species. Due to their high mutability, an adaptive role for microsatellites has been considered. However, little is known concerning the contribution of microsatellites towards phenotypic variation. We used populations of the common sunflower (Helianthus annuus) at two latitudes to quantify the effect of microsatellite allele length on phenotype at the level of gene expression. We conducted a common garden experiment with seed collected from sunflower populations in Kansas and Oklahoma followed by an RNA-Seq experiment on 95 individuals. The effect of microsatellite allele length on gene expression was assessed across 3,325 microsatellites that could be consistently scored. Our study revealed 479 microsatellites at which allele length significantly correlates with gene expression (eSTRs). When irregular allele sizes not conforming to the motif length were removed, the number of eSTRs rose to 2,379. The percentage of variation in gene expression explained by eSTRs ranged from 1%-86% when controlling for population and allele-by-population interaction effects at the 479 eSTRs. Of these eSTRs, 70.4% are in untranslated regions (UTRs). A gene ontology (GO) analysis revealed that eSTRs are significantly enriched for GO terms associated with cis- and trans-regulatory processes. Our findings suggest that a substantial number of transcribed microsatellites can influence gene expression.


Subject(s)
Genetics, Population , Helianthus , Microsatellite Repeats , Alleles , Gene Expression , Helianthus/genetics , Kansas , Oklahoma
9.
Pediatr Pulmonol ; 55(6): 1495-1502, 2020 06.
Article in English | MEDLINE | ID: mdl-32289209

ABSTRACT

BACKGROUND: To date there are limited data in the literature to guide the initial evaluation for etiologies of apnea in full-term infants born at greater than or equal to 37 weeks conceptional age (apnea of infancy [AOI]). Pediatricians and pediatric pulmonologists are left to pursue a broad, rather than targeted and a stepwise approach to begin diagnostic evaluation. METHODS: We performed a retrospective chart review of 101 symptomatic full-term infants (age under 12 months) diagnosed with apnea with an inpatient multichannel pneumogram (six channels) or a fully attended overnight pediatric polysomnogram in our outpatient sleep center accredited by American Academy of Sleep Medicine (AASM), scored using the standards set forth by the AASM. The infant was diagnosed as having AOI if the apnea hypopnea index (AHI) was greater than 1 (AHI is defined as the number of apnea and hypopnea events per hour of sleep). The final diagnosis/etiology was determined based on physician clinical assessment and work up. We then determined the frequency for each diagnosis. RESULTS: We found that the three most common etiologies were gastroesophageal reflux disease (GERD) (48/101), upper airway abnormalities/obstruction (37/101), and neurological diseases (19/101). There were significant numbers of infants with multiple etiologies for AOI. CONCLUSION: Based on the frequencies obtained, pediatric practitioners caring for full-term infants with apnea of unknown etiology are advised to begin with evaluation of more likely causes such as GERD and upper airway abnormalities/obstruction before evaluating for less common causes.


Subject(s)
Gastroesophageal Reflux/complications , Nervous System Diseases/complications , Respiratory System Abnormalities/complications , Sleep Apnea Syndromes/etiology , Female , Gastroesophageal Reflux/diagnosis , Gastroesophageal Reflux/physiopathology , Humans , Infant , Infant, Newborn , Male , Nervous System Diseases/diagnosis , Nervous System Diseases/physiopathology , Polysomnography , Respiratory System Abnormalities/diagnosis , Respiratory System Abnormalities/physiopathology , Retrospective Studies , Sleep Apnea Syndromes/diagnosis , Sleep Apnea Syndromes/physiopathology
10.
Ecol Evol ; 10(7): 3424-3438, 2020 Apr.
Article in English | MEDLINE | ID: mdl-32273999

ABSTRACT

The decision of females to nest communally has important consequences for reproductive success. While often associated with reduced energetic expenditure, conspecific aggregations also expose females and offspring to conspecific aggression, exploitation, and infanticide. Intrasexual competition pressures are expected to favor the evolution of conditional strategies, which could be based on simple decision rules (i.e., availability of nesting sites and synchronicity with conspecifics) or on a focal individual's condition or status (i.e., body size). Oviparous reptiles that reproduce seasonally and provide limited to no postnatal care provide ideal systems for disentangling social factors that influence different female reproductive tactics from those present in offspring-rearing environments. In this study, we investigated whether nesting strategies in a West Indian rock iguana, Cyclura nubila caymanensis, vary conditionally with reproductive timing or body size, and evaluated consequences for nesting success. Nesting surveys were conducted on Little Cayman, Cayman Islands, British West Indies for four consecutive years. Use of high-density nesting sites was increasingly favored up to seasonal nesting activity peaks, after which nesting was generally restricted to low-density nesting areas. Although larger females were not more likely than smaller females to nest in high-density areas, larger females nested earlier and gained access to priority oviposition sites. Smaller females constructed nests later in the season, apparently foregoing investment in extended nest defense. Late-season nests were also constructed at shallower depths and exhibited shorter incubation periods. While nest depth and incubation length had significant effects on reproductive outcomes, so did local nest densities. Higher densities were associated with significant declines in hatching success, with up to 20% of egg-filled nests experiencing later intrusion by a conspecific. Despite these risks, nests in high-density areas were significantly more successful than elsewhere due to the benefits of greater chamber depths and longer incubation times. These results imply that communal nest sites convey honest signals of habitat quality, but that gaining and defending priority oviposition sites requires competitive ability.

11.
J Hered ; 110(7): 818-829, 2019 12 17.
Article in English | MEDLINE | ID: mdl-31617903

ABSTRACT

Inbreeding depression, though challenging to identify in nature, may play an important role in regulating the dynamics of small and isolated populations. Conversely, greater expression of genetic load can enhance opportunities for natural selection. Conditional expression concentrates these opportunities for selection and may lead to failure of detection. This study investigates the possibility for age-dependent expression of inbreeding depression in a critically endangered population of rock iguanas, Cyclura nubila caymanensis. We employ heterozygote-fitness correlations to examine the contributions of individual genetic factors to body size, a fitness-related trait. Nonsignificant reductions in homozygosity (up to 7%) were detected between neonates and individuals surviving past their first year, which may reflect natural absorption of inbreeding effects by this small, fecund population. The majority of variation in neonate body size was attributed to maternal or environmental effects (i.e., clutch identity and incubation length); however, heterozygosity across 22 microsatellite loci also contributed significantly and positively to model predictions. Conversely, effects of heterozygosity on fitness were not detectable when adults were examined, suggesting that inbreeding depression in body size may be age dependent in this taxon. Overall, these findings emphasize the importance of taking holistic, cross-generational approaches to genetic monitoring of endangered populations.


Subject(s)
Body Size/genetics , Genetic Fitness , Heterozygote , Iguanas/genetics , Inbreeding Depression , Quantitative Trait Loci , Animals , Genetic Markers , Genetic Variation , Selection, Genetic
12.
Ecol Evol ; 9(14): 8331-8350, 2019 Jul.
Article in English | MEDLINE | ID: mdl-31380093

ABSTRACT

Cyclura ricordii is an endemic iguana from Hispaniola Island and is threatened on the IUCN Red List. The main threats are predation by introduced mammals, habitat destruction, and hunting pressure. The present study focused on two nesting sites from Pedernales Province in the Dominican Republic. The hypothesis that natal philopatry influences dispersal and nest-site selection was tested. Monitoring and sampling took place in 2012 and 2013. Polymorphic markers were used to evaluate whether natal philopatry limits dispersal at multiple spatial scales. Ripley's K revealed that nests were significantly clustered at multiple scales, when both nesting sites were considered and within each nesting site. This suggests a patchy, nonrandom distribution of nests within nest sites. Hierarchical AMOVA revealed that nest-site aggregations did not explain a significant portion of genetic variation within nesting sites. However, a small but positive correlation between geographic and genetic distance was detected using a Mantel's test. Hence, the relationship between geographic distance and genetic distance among hatchlings within nest sites, while detectable, was not strong enough to have a marked effect on fine-scale genetic structure. Spatial and genetic data combined determined that the nesting sites included nesting females from multiple locations, and the hypothesis of "natal philopatry" was not supported because females nesting in the same cluster were no more closely related to each other than to other females from the same nesting site. These findings imply that nesting aggregations are more likely associated with cryptic habitat variables contributing to optimal nesting conditions.

13.
Mitochondrial DNA B Resour ; 4(2): 2479-2481, 2019 Jul 12.
Article in English | MEDLINE | ID: mdl-33365591

ABSTRACT

The Lesser Antillean iguana, Iguana delicatissima Laurenti 1768, is one of the most endangered vertebrate taxa in the West Indies. This species faces significant threats, including introgressive hybridization with the introduced congener Iguana iguana. We deploy a combination of off-target sequence capture obtained from Illumina® reads and targeted Sanger reads to assemble the mitochondrial genome of I. delicatissima. The mitogenome is 16,616 bp in length and is comprised of 13 protein-coding genes, two ribosomal subunits (rRNAs), 22 transfer RNAs, and a control region. Gene order is identical to that of congener I. iguana and other closely related taxa, absent of any tandem repeat regions. We show the phylogenetic utility of the mitogenome with a maximum-likelihood analysis, which yields a topology concordant with previous studies of iguanine taxa. We are hopeful that this genomic resource will be useful in further informing applied conservation and management for this critically endangered species.

14.
J Oral Maxillofac Surg ; 77(5): 1073.e1-1073.e11, 2019 May.
Article in English | MEDLINE | ID: mdl-30557529

ABSTRACT

A 61-year-old woman who lost her nose, upper lip, and most of her midface bony structures because of cancer 20 years previously underwent advanced surgical reconstruction. This patient previously underwent multiple reconstructive surgeries that failed to satisfactorily restore her nose. Therefore, a multistage reconstruction was performed to recreate a complete nose and increase her upper lip length. Because of a lack of sufficient facial bone and nasal supporting structures, the reconstruction was extremely challenging. Virtual surgical planning technology was used to create a customized titanium nasal plate. The patient's nose was successfully reconstructed using the nasal plate, costal cartilage, and a paramedian forehead flap. The patient is highly satisfied with the cosmetic and functional results and has had marked psychosocial improvement since the reconstruction.


Subject(s)
Nose Neoplasms , Plastic Surgery Procedures , Rhinoplasty , Female , Forehead , Humans , Middle Aged , Nose , Nose Neoplasms/surgery , Surgical Flaps
15.
ACS Synth Biol ; 7(7): 1730-1741, 2018 07 20.
Article in English | MEDLINE | ID: mdl-29782150

ABSTRACT

Directed evolution experiments designed to improve the activity of a biocatalyst have increased in sophistication from the early days of completely random mutagenesis. Sequence-based and structure-based methods have been developed to identify "hotspot" positions that when randomized provide a higher frequency of beneficial mutations that improve activity. These focused mutagenesis methods reduce library sizes and therefore reduce screening burden, accelerating the rate of finding improved enzymes. Looking for further acceleration in finding improved enzymes, we investigated whether two existing methods, one sequence-based (Protein GPS) and one structure-based (using Bioluminate and MOE), were sufficiently predictive to provide not just the hotspot position, but also the amino acid substitution that improved activity at that position. By limiting the libraries to variants that contained only specific amino acid substitutions, library sizes were kept to less than 100 variants. For an initial round of ATA-117 R-selective transaminase evolution, we found that the methods used produced libraries where 9% and 18% of the amino acid substitutions chosen were amino acids that improved reaction performance in lysates. The ability to create combinations of mutations as part of the initial design was confounded by the relatively large number of predicted mutations that were inactivating (30% and 45% for the sequence-based and structure-based methods, respectively). Despite this, combining several mutations identified within a given method produced variant lysates 7- and 9-fold more active than the wild-type lysate, highlighting the capability of mutations chosen this way to generate large advances in activity in addition to the reductions in screening.


Subject(s)
Directed Molecular Evolution , Mutagenesis/genetics , Mutation/genetics
16.
Ecol Evol ; 8(4): 2088-2096, 2018 02.
Article in English | MEDLINE | ID: mdl-29468027

ABSTRACT

Inbreeding depression can have alarming impacts on threatened species with small population sizes. Assessing inbreeding has therefore become an important focus of conservation research. In this study, heterozygosity-fitness correlations (HFCs) were measured by genotyping 7 loci in 83 adult and 184 hatchling Lesser Antillean Iguanas, Iguana delicatissima, at a communal nesting site in Dominica to assess the role of inbreeding depression on hatchling fitness and recruitment to the adult population in this endangered species. We found insignificant correlations between multilocus heterozygosity and multiple fitness proxies in hatchlings and adults. Further, multilocus heterozygosity did not differ significantly between hatchlings and adults, which suggests that the survivorship of homozygous hatchlings does not differ markedly from that of their heterozygous counterparts. However, genotypes at two individual loci were correlated with hatching date, a finding consistent with the linkage between specific marker loci and segregating deleterious recessive alleles. These results provide only modest evidence that inbreeding depression influences the population dynamics of I. delicatissima on Dominica.

17.
J Hered ; 109(4): 426-437, 2018 05 11.
Article in English | MEDLINE | ID: mdl-29471487

ABSTRACT

The Lesser Antillean Iguana (Iguana delicatissima) is an endangered species threatened by habitat loss and hybridization with non-native Green Iguanas (Iguana iguana). Iguana delicatissima has been extirpated on several islands, and the Green Iguana has invaded most islands with extant populations. Information is essential to protect this species from extinction. We collected data on 293 iguanas including 17 juveniles from St. Eustasius, one of the few remaining I. delicatissima strongholds. Genetic data were leveraged to test for hybridization presence with the Green Iguana using both mitochondrial and nuclear genes, including 16 microsatellite loci. The microsatellites were also analyzed to estimate genetic diversity, population structure, and effective population size. Using molecular and morphological data, we identified 286 I. delicatissima individuals captured during our first fieldwork effort, and 7 non-native iguanas captured during a second effort, showing hybridization occurs within this population. Comparing homologous microsatellites used in studies on Dominica and Chancel, the I. delicatissima population on St. Eustatius has extremely low genetic diversity (HO = 0.051; HE = 0.057), suggesting this population is genetically depauperate. Furthermore, there is significant evidence for inbreeding (FIS = 0.12) and weak spatial genetic structure (FST = 0.021, P = 0.002) within this population. Besides immediate threats including hybridization, this population's low genetic diversity, presence of physiological abnormalities and low recruitment could indicate presence of inbreeding depression that threatens its long-term survival. We conclude there is a continued region-wide threat to I. delicatissima and highlight the need for immediate conservation action to stop the continuing spread of Green Iguanas and to eliminate hybridization from St. Eustatius.


Subject(s)
Genetic Variation , Genetics, Population , Iguanas/genetics , Microsatellite Repeats/genetics , Animals , Breeding , Conservation of Natural Resources , Ecosystem , Endangered Species , Female , Hybridization, Genetic , Islands , Male , Population Density
18.
Mol Ecol ; 27(5): 1188-1199, 2018 03.
Article in English | MEDLINE | ID: mdl-29419922

ABSTRACT

The mechanisms by which natural populations generate adaptive genetic variation are not well understood. Some studies propose that microsatellites can function as drivers of adaptive variation. Here, we tested a potentially adaptive role for transcribed microsatellites with natural populations of the common sunflower (Helianthus annuus L.) by assessing the enrichment of microsatellites in genes that show expression divergence across latitudes. Seeds collected from six populations at two distinct latitudes in Kansas and Oklahoma were planted and grown in a common garden. Morphological measurements from the common garden demonstrated that phenotypic variation among populations is largely explained by underlying genetic variation. An RNA-Seq experiment was conducted with 96 of the individuals grown in the common garden and differentially expressed (DE) transcripts between the two latitudes were identified. A total number of 825 DE transcripts were identified. DE transcripts and nondifferentially expressed (NDE) transcripts were then scanned for microsatellites. The abundance of different motif lengths and types in both groups were estimated. Our results indicate that DE transcripts are significantly enriched with mononucleotide repeats and significantly depauperate in trinucleotide repeats. Further, the standardized mononucleotide repeat motif A and dinucleotide repeat motif AG were significantly enriched within DE transcripts while motif types, C, AT, ACC and AAC in DE transcripts, are significantly differentiated in microsatellite tract length between the two latitudes. The tract length differentiation at specific microsatellite motif types across latitudes and their enrichment within DE transcripts indicate a potential functional role for transcribed microsatellites in gene expression divergence in sunflower.


Subject(s)
Gene Expression Profiling , Gene Expression Regulation, Plant , Helianthus/genetics , Microsatellite Repeats/physiology , Adaptation, Biological , Genes, Plant , Genetic Variation , Helianthus/growth & development , Helianthus/metabolism , Kansas , Oklahoma , Phenotype , Sequence Analysis, RNA
19.
Angiology ; 68(2): 119-123, 2017 Feb.
Article in English | MEDLINE | ID: mdl-27178717

ABSTRACT

We evaluated our experience following the introduction of a percutaneous endovascular aneurysm repair (pEVAR) first approach using Perclose Proglide assessing efficacy, complications, and identification of factors that could predict failure. A retrospective cohort study on patients over a 2-year period following the introduction of a pEVAR first approach was performed. The primary end point was defined as successful deployment and access site hemostasis. Percutaneous EVAR was technically successful in 41 (77.4%) of 53 patients and 83 (86.5%) of 96 access sites. Factors associated with failure were smaller common femoral artery (CFA) diameter ( P = .045) and CFA circumferential calcification of greater than 50% ( P = .0001). The incidence of access site infection was significantly higher in the failure group ( P = .008) as was procedure duration ( P = .026). Percutaneous EVAR first approach must be introduced with caution. Percutaneous EVAR failure occurs more often in patients with unfavorable access site anatomy. Success rate can be improved with careful patient selection.


Subject(s)
Aneurysm/surgery , Endovascular Procedures/methods , Aged , Aneurysm/diagnostic imaging , Computed Tomography Angiography , Female , Hemostasis, Surgical , Humans , Incidence , Male , Patient Selection , Postoperative Complications/epidemiology , Retrospective Studies , Risk Factors , Treatment Outcome
20.
PeerJ ; 4: e1793, 2016.
Article in English | MEDLINE | ID: mdl-26989628

ABSTRACT

The Endangered Allen Cays Rock Iguana (Cyclura cychlura inornata) is endemic to the Allen Cays, a tiny cluster of islands in the Bahamas. Naturally occurring populations exist on only two cays (<4 ha each). However, populations of unknown origin were recently discovered on four additional cays. To investigate patterns of genetic variation among these populations, we analyzed nuclear and mitochondrial markers for 268 individuals. Analysis of three mitochondrial gene regions (2,328 bp) and data for eight nuclear microsatellite loci indicated low genetic diversity overall. Estimates of effective population sizes based on multilocus genotypes were also extremely low. Despite low diversity, significant population structuring and variation in genetic diversity measures were detected among cays. Genetic data confirm the source population for an experimentally translocated population while raising concerns regarding other, unauthorized, translocations. Reduced heterozygosity is consistent with a documented historical population decline due to overharvest. This study provides the first range-wide genetic analysis of this subspecies. We suggest strategies to maximize genetic diversity during ongoing recovery including additional translocations to establish assurance populations and additional protective measures for the two remaining natural populations.

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